Well, since it's just seemingly random things that'll get suggested...
Weightlifting!
[youtube]http://www.youtube.com/watch?v=GUl7UqbL3uc[/youtube]
Olympic style lifting is loads of fun for me. I don't have any really impressive lifts yet, but it's so so fun for some reason. You're putting a heavy barbell over your head really quickly. You feel pretty awesome when you do it. There's also powerlifting, too. Powerlifting is benchpress, squat, and deadlift, 3 lifts, more max strength oriented while Olympic lifting takes more balance/dexterity/reflexes and the like. One warning about OL lifting, though, I'm insane and tried the lifts myself with zero coaching, but generally that's not the recommended thing to do, and OL coaching is a bit expensive in my experience, and a lot of gyms don't have bumper plates so you can't do the lifts properly. Also it helps to have weightlifting shoes, too, which are $100ish, whereas powerlifting tends to be cheaper and instruction is easier to get, you can do it in most gyms, and then cheap crappy shoes like Converse or the like are best for powerlifting.
Ice skating!
Figure Skating
Speed Skating
I do figure, it sorta happened on accident. I decided to go ice skating, and used hockey skates, after not going ice skating since I was a kid, and I saw the figure skaters on the ice and was like "wow...." and then "I wanna be as fast as them and do those cool turns and stuff." And then one day I ended up buying figure skates, and yeah. I've tried speed skating, though, and it's great fun, it's a bit less OCD of a hobby than figure skating. Both are a bit of a "rich man's sport" but if they'll let you use speed skates on public ice (99% of the time figure skates are fine on public ice,) public ice tends to run like $5 a session, but some places offer discount passes, like my rink if you join their affiliated gym next door, you pay $30 a month for the entire gym you can use, and get the public ice time.
Of course, you can always play hockey, hockey a lot of times attracts a bit more of a "bro" crowd of people, though. Adult hockey leagues cost like $300-400 for I think 12 games (if you don't make playoffs) and then you'll need about $100ish equipment plus skates to start off. If you got the equipment and just wanna play without committing to a team, there's sticktime and the like, where you pay $10-20 a session, and just need gear, and you either play pickup games with whoever shows up, or there's sessions where you can just shoot around without playing "against" people. Hockey, you don't gotta worry about your fitness level at first, either, I've seen plenty of 300lb dudes playing Tier 4 (beginnerish league) games (erm, I don't know if you're 300lbs, in shape, or not, I'm just saying don't worry about being too out of shape.) Hockey is a bit more of a social sport, though, so keep that in mind.
Of course also, if you got no ice in your area, there's also the inline or quad skate equivalents of these sports. You'd do yourself good if you just got a decent pair of inlines and found a trail/street without traffic and just did some inline skating on it, too.
I said all these as these are things I do currently, so I can speak direct experience about them.
Two other good physical hobbies I've done are cycling and hiking. Both of those are good, you can do them alone, and they don't take terribly high amounts of money to do and they'll contribute to a good physical condition.
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I like getting out of my house. My house has too many people in it who annoy me.