Role playing game

"Dungeons and Dragons" being the most popularly known. While most RPGs center around elaborate combat rules, at its heart it is really improvisational acting. You're acting the role of a character thrust into various situations and must always be answering the critical question "what do you do?"

RPGs run the spectrum from traditional the "dungeon crawl" / "kill people and take their stuff" of "Dungeons and Dragons" to the almost entirely free form and diceless "Amber" with the "Storyteller" series ("Vampire", "Mage", "Werewolf"...) sitting somewhere in the middle. WoW is firmly in the "kill people and take their stuff" camp.

The major advantage of computerized RPGs is they handle all the rules, mechanics and die rolling for you letting you focus on just the role playing / whacking monsters on the head. The disadvantage is the computer is not nearly as flexible as a human game master and thus computerized RPGs tend to be shallow and linear with little actual "role playing". Online RPGs (such as WoW) partially fix this problem by at least giving you other humans to interact with, but the game master is still a computer and thus quests and NPC interactions are shallow.