There is also a non-card game that my friends and I play called bastard. It is quite juvenile and it's origins are unknown to me (one of my friends may/probably made it up) but, all in all, it can be a very enjoyable game.
The base concept is extremely simple. Two people play the game, whenever they see each other the first person to call the other bastard wins. This goes on until it is deemed boring. One can see how this would quickly escalate in to screaming bastard at your foe from across a crowded room, or setting up ambushes, and of course arguments over who won (which invariably boil down to infantile name calling).
As a result of possibly infinite game play (I know of a game that's gone on for four years) rules are can be modified as seen fit. We have chosen to score in winning streaks (number of successful bastards between being bastardized yourself), as well as bonus respect for creative bastards. (ie placing a note in a friends book, or elaborate plots that can rival the planning that went into the patriot act’s name)
Ultimately this game is childish and dangerous, (ever mistaken a stranger for a friend when you saw them walking away? Think what could happen.) and definitely more enjoyable to watch than play.