Then the important part starts. The players begin to play, by talking, in turn, the Game Master describing the situation, and the players each stating what their character does. When there is a conflict situation, and a character's action may or may not succeed, rules are consulted and typically dice are rolled to determine the results, based on the action, the situation, and the character's statistics. With the advent of the Internet, these games are sometimes played not physically face to face, but through email or chat rooms, but these last principles remain the same.

There are many systems of rules and settings that people play roleplaying games in, and when people say they are buying a roleplaying game, this is what they are buying, the books of rules and settings. Sometimes the rules system can be separate from the setting, but often they come as a package, this set of rules with this world.

Rules systems vary from the very detailed and complex, to the vaguer, and more simple, requiring more judgement and discretion from the gamemaster to decide the result of actions. Most rules systems use dice to determine the results of actions, which are compared with the characters' characteristics and looked up in tables. Some other games, like Everway, and Castle Falkenstein, use cards instead of dice to provide the element of chance. Yet others, so called "diceless" systems, like Amber, don't use any random element at all, and rely on the Game Master's judgement of the character's characteristics, and the way the player describes an action.

Settings, or Worlds for games also vary. Many games use a specific world, such as one from literature, where many of the places and people are already determined by the authors. Others allow for more about the world to be determined by the Game Master, and just provide rules and scenarios that will fit a specific Genre, for example the lair of an evil dragon that will fit nearly any Game Master's Fantasy world. Yet other systems try to be completely generic, and fit any setting the Game Master has in mind.

Live Action involves dressing up and acting out your character's actions, in various settings or rules systems, while "Tabletop" or "Pencil and Paper" games are usually played sitting around a table, with all the characters actions taking place in the imagination.

The first, and still most popular, "tabletop" roleplaying game is TSR's (now Wizards of the Coasts) Dungeons and Dragons, set in medieval fantasy. Other popular games systems include White Wolf's dark modern Vampire: The Masquerade, FASA's cyber-fantasy Shadowrun, Hero Games' superhero Champions, Chaosium's 1920s horror Call of Cthulhu, Steve Jackson's generic system GURPS, and Palladium's mixed setting Rifts. There are hundreds of others, and each group usually comes up with "house rules" of their own, many of which even evolve into independent Free RPGs.

Different roleplaying game worlds and systems use different rules, and therefore terms. However, there is a common subset of these terms that means much the same thing in many games, a sort of jargon. This section attempts to explain these terms roleplayers often use.

"I'll be judge, I'll be jury," said cunning old Fury: "I'll try the whole cause, and condemn you to death."

The Game Master (or Games Master, or Judge, or Referee, or GM), is the player responsible for everything in the imaginary world except for the player characters, from non-player characters (NPCs), to inanimate events like the weather. The GM generally creates (or buys) materials to describe the settings that players play in, from individual adventure scenarios, or campaigns of multiple linked scenarios, to the world those adventures take place in, ahead of time. Then the GM controls the way the non-player characters react to the player characters, and each other, as the game progresses. Finally, the GM enforces the rules of the game, and makes up new rules, as needed, to determine the effects of characters' actions.

Being a Games Master is a different sort of task than being a Player. Some roleplayers can't stand to be the gamemaster, others prefer it, yet others can enjoy playing either way. There is a lot more power, and a lot more responsibility. It is important the GM not see their role as being in competition with the Players, even though many of the NPCs the GM controls will be. Instead, it is the GM's role to provide an interesting and exciting adventure.

Not all games use the words Game Master to describe this position. Dungeons & Dragons calls this position Dungeon Master, or DM, so this is what many players know this position as. Other games use other game-specific names, "Keeper", for Call of Cthulhu, for example. Finally, there are the names some players call their Game Master when their favorite character is killed, mostly unprintable, of course. But the role of the Game Master in each case is generally similar.

A Player Character, or PC, is the individual role, or fictional persona, played by a roleplayer. In most roleplaying games, all players but the Game Master have a single PC, that they develop. These PCs are usually described by numerical characteristics depending on the system - so strong, so fast, so healthy, so skilled with using a sword or flying a spaceship - in a way that can be compared to other PCs, and that can be used in the game system. "Hercules, with a Strength of 25, is stronger than Aragorn, with a Strength of 17. To lift this large rock, roll 5 six-sided dice under the character's Strength." These characteristics are usually determined once, in a process called "character creation", sometimes rolled with dice, or other system tools, sometimes "bought" from an allocation of points. PCs are normally created before the start of a gaming session, usually with interaction between the player who is to "run" the character, the rules system being used, and the Game Master, who has to approve that a character "fit in" to the game world. As there are usually several players and one game master, there are usually several Player Characters, and these are often referred to as "the party". These usually work together to solve the problems the Game Master's world presents them.

NPCs, or gamemaster controlled characters, are often described using similar characteristics, but usually in less detail, simply because the GM has to spread their creativity over a whole world of NPCs. PCs, on the other hand, are usually very detailed, with distinct personalities, likes and dislikes, motivations, goals, and life histories. Developing an interesting, believable PC is usually one of the goals of roleplayers.

Often, in so far as a roleplaying game has a more concrete and measurable goal, that goal is for the players to advance and develop their PCs, as they become more experienced and more powerful. Players often become attached to their PCs, through the effort they spent imagining, creating, developing and playing the character, and when one "dies" in an adventure, it can be a dramatic moment. However, it is still part of the game, and another PC is usually rolled up for the next session.

• A "Real Man", or, probably more accurately, a "Real Gamer", since there are plenty of women like this, plays the roleplaying game as a game first, just one with a more interesting and flexible set of rules and goals than chess or volleyball. A "Real Gamer" is interested in matching their character's abilities against the imaginary world, and the non-player characters. The character's personality is interesting as part of the rules of the game, but not in itself, only as it affects playing the game. This type of player is likely to also be interested in other games, Computer and Video Game RPGs, Wargames, and so forth, but they can tell the difference.
• A "Real Roleplayer" plays a roleplaying game as roleplaying first, and a game second. This kind of player is interested in developing the character's personality, history, and motivations, in depth. The game is useful as a background in helping develop that personality, to see how the character will react to interesting, dramatic, and challenging situations. This is the type of player most likely to be interested in "chat roleplaying" or collaborative fiction without the constraints of rules.
• A "Loony" is interested in the game as a social event, the way some people play Party Games, more to draw friends together and to give them something enjoyable to do. They try to emphasize the "it's only a game" aspect, and to keep other players from becoming obsessed with what can be a very involving pastime. The name comes from the fact that they tend to have their characters make jokes and do funny things, to lighten the mood, which can be quite serious when only "Real Gamers" and "Real Roleplayers" are playing.
• Finally, a "Munchkin" is playing to "win", and doesn't really understand that the point of this game at least, is not to win, but just to play. A Munchkin is the most likely to want to create extremely powerful characters, and to try to find abuses and loopholes in the rules to, again, give their characters more power. A Munchkin is the most likely to confuse Roleplaying Games with the other games that call themselves RPGs, such as Computer and Video Game RPGs, and not see the difference. Munchkins tend to be the younger players, those newer to roleplaying, and even the name comes from the "short people with high pitched voices" from The Wizard of Oz book and movie. Other roleplayers tend to look down on them, as undeveloped.

Most roleplaying games determine the results of characters' actions, and other events that have an element of chance, by rolling dice. The events to be simulated are often complicated, so many games use more than just the standard, cubical, six-sided, dice. 3d6, 2d10, 1d100, are examples of the notation used to specify the number and kind of dice rolled. The first number in the notation specifies how many dice are rolled, the "d" is short for "die", or "dice", and the second number is the number of sides on each die. If a constant should be added to or subtracted from the die roll it is written after the dice notation with the appropriate symbol. For example, 2d6+6 means the sum of 2 six-sided dice and 6.

The standard, six-sided, die is a d6. A "classical" d4 is a triangular pyramid, numbered along the edges of each face. A d8 is an octahedron, like two rectangular pyramids joined at the base. A d10 is the only non-platonic solid among the common dice, like two pentagon-based pyramids joined at the base. A d12 is an dodecahedron, with pentagon faces. A d20 is an icosahedron, with triangular faces. Other ranges are usually made by rolling a greater die, and reading it a special way, for example to imitate 1d3, rolling 1d6 and counting 1-2 as 1, 3-4 as 2, 5-6 as 3. A d100, also sometimes called d%, or the "percentile die", is rolled by rolling 2d10, but instead of summing them, reading the first as the "tens" digit, and the second as the "units" digit. A roll of 10 and 10 is usually read as 100 but sometimes as 0, depending on the games system.

Other dice have been made for special uses or specific game systems, such as with non-standard numbering, symbols instead of numbers or pips on some or all of the faces, or with an unusual number of faces, such as the 30-sided die, or the true 100-sided die (it was much like a golf ball), but the above are the most popular dice. Finally, many roleplaying systems do not use dice at all.

Hit points are another concept common to most, but not all, roleplaying games, under one name or another (stun points, body points, wound points, health points...). Character actions often involve fighting, and injury or death. Hit points are a common abstraction that quantify each character's resistance to injury into a single number. The more hit points a character has, the harder they are to kill - a large dragon would typically have more hit points than a small dog. Each injury, or "damage", reduces the character's hit point total, and the more severe the injury, the more hit points it does as damage - a large axe would tend to do more damage than a small knife. Typically when a character's hit points reach 0 they are either dead, or incapacitated and not far from death.

Hit points have been criticized as an unrealistic abstraction, since most living beings' reaction to injury is more complicated than just summing up wounds. Some systems dispense with a single hit point number, or use a mixture of hit points with other mechanisms, such as hit location, individual wound effects, etc. But using a single hit points number does simplify matters, and also gives a warning so players can tell when their character is close to death, and can consider other options such as making peace, retreat, or surrender.