Archery is awesome but pretty expensive (the price of good arrows is absolutely stupid). That is one of my hobbies (recurve bow onry, none of that compound shit) and now that it's getting warm...wish I didn't live in a dorm >_> But it's a good hobby to undertake if financially possible, strengthens the arms and is just a cool skill to have/show off.
Other things to do... learn to juggle if you can't, it's relatively simple (just takes time to learn) and def. impresses the ladies. It's something you can bust out anywhere and look awesome at provided you don't drop shit. Alternatively, learn to play Go or Mahjong or some kind of fancy game. Or play online poker (can win $$ on it, if only a little bit). I know quite a few people who are all over that because it's fun as hell to them. My personal current hobby is
diabolo, it's very satisfying and fun (and doesn't cost too much to get equipment for unless you get the triple-bearing one I got XD).