A resident of mine and a friend invented a game where players take turns rolling a bottle cap (like from a 16-oz juice) accross the hall and hopefully into the goal set up by the other person's fingers. Tonight, another guy added the challenge of a bouncing tennis ball trying to hit the cap.
And for some reason, this is an entertaining spectator sport.
On my hall last year the game was to see how many people they could sleep with in a single academic year. It was a co-ed hall, so I guess this could be deemed a house activity... I, needless to say, didn't participate in that particular, uh, spectator sport?
In high school, my friends and I had a similar game, except instead of using bottle caps we used quarters. The challenge became who could roll their quarter furthest down the hallway without 1) it falling over, 2) it hitting something/someone, 3) someone taking it for soda money (which generally happened after #2). Entertainment, indeed! :)