I recently went on a retreat with my youth group to Camp Christian in Burns, TN. It was a really great weekend. The kids were well-behaved and participated really well. I had good help from the parents, and therefore we also had great food to eat and snack on. I also discovered a new game while I was there called Carpet Ball.
The game is like a dumbed down version of pool. You have a long wooden table kind of like a trough with a carpet-coated interior. (Apparently, it looks best when you use superbad 1970's carpet like what is pictured) You use one set of pool balls (solids on one end, stripes on the other). At each end of the table is a big pocket where the balls can be knocked into.
Each person sets up his/her balls in whatever way they desire, then the two players take turns pushing the pool cue ball towards their opponents' balls. The goal is to knock the other balls in without the cue ball going into the pocket. If the cue ball goes into the pocket, then whatever balls were knocked in that particular turn are taken back out and placed again on the table wherever the player desires within the lined-off area. The game is over when one person knocks all of the other person's balls into the pocket.
It doesn't look like it'd be that hard to build one. It was a lot of fun!