I have a heavily modified version of the Killmonster game (found somewhere on the net) which makes use of the threads user table. It is a very simple script where you attack monsters by selecting them from a dropdown list and it is randomized if you win or loose and you get som experience points depending on how hard the monster was. It is also possible to kill other users and gain a percentage of their experience points. The looks isn't integrated into threads, but that shouldn't be too hard as I use a similiar template method as threads do.
The admin can set up all the monsters themselves and decide the toughness and experience points gained when they are killed.
Not very family oriented, I know, but still a bit of fun. =]