I've been practicing Taekwondo for about 7 months so far and am now a yellow belt. It's definitely fun for me, since I used to do fake martial arts when no one was looking. Also, I found many of the fellow members to be of the sort you'd find on the escapist, rather than the usual, "Did you catch the big game after golf yesterday?" type that I find at work. Geek culture is pleasantly prevalent there.