I here the UQ colleges are good, I don't know about sport participation but most colleges like you to participate.
Drinking is nearly a must but you can get away if you seriously aren't - but you may get converted like myself.
I think you've chosen one of the better and more conservative UQ colleges so you may not be able to muck up as much.
Remember to bring a computer with a network card as UQ has an amazing college network (full of ripped movies/music etc).
I don't think there's really that much 'groups' as there was in school as people seem more similar or have left their older ways to some degree but of course you still have the big ones, like the geeks, footies and beautiful girls, but there's more (and probably the majority) of the normal crowd.
Keen