RPG
A Role-Playing Game is a game in which you create a character and have relative freedom in choice. The best RPGs are tabletop/pen-and-paper style, closely followed by those run on IRC channels, because computer RPGs are incredibly limited in choice due to the relatively small amount of information they can contain.

Contrary to popular belief, the more recent games in the Final Fantasy series were not RPGs as such, because you had very little control over the storyline, and the character. I'm not sure at this point in time what genre they were, but despite the level-up system, the games weren't RPGs.
Dungeons and Dragons is a perfect sword/sorcery style RPG, while Spycraft fits the bill for anyone interested in espionage.