There's a lot of CFers who do martial arts. Sometimes I think 80% of the CF playerbase is programmer martial-artists.

I study Uechi-Ryu and have done some BJJ, Aikido and Kempo. Uechi-ryu is a simple (in terms of not having a huge number of core techniques and katas) utility-oriented stand-up martial art. It is a close-range style that heavier on hand strikes more than kicks, though there are both.

Historically, it's a descendant of pangainoon, which is a style of chinese kung fu. It was brought to Okinawa by Uechi Kanbun and to the US in the fifties by George Mattson.

There are a number of variants and organizations these day. I've been in the IUKF under sensei Vincent Christiano for 5 or 6 years and my rank is shodan. Different Uechi dojos have different levels of discipline, though they tend to be less regimented than many traditional styles. There are some that are strictly formal however. Where I study we tend to dispense with most of that, we still bow in and out and to each other when doing drills, but we call the teacher Vinny instead of sensei and it's generally a relaxed atmosphere as far as formality goes.

I've been looking into studying Judo at a place nearby that has a good reputation.

Edit:
I've also done a little bit of Kali in seminars and found it interesting. I've done it with a guy named Raffi Derderian and with Wes Tasker whose style is Pakiti Tirsha (probably mispelled). It's neat stuff.