In smaller (4-8 people) parties, we have done strip rummy. The winner of each round removes an article of clothing. Once naked, if you win a round, the person of the opposite sex with the lowest score gives you oral, but not to completion. This goes on until someone hits the pre determined winning score. The game winner is the first to get to completion, in the manner of their choosing.
Sometimes we get to the end of the game, sometimes we don’t.
Yahtzee also works well because of how many lines to play the game.