I know a bit of "unscientific" martial arts. (I am by no means an expert). Though I prefer to use my skill of finding objects that make good (albeit unconventional) weapons.
My sister's a black belt
I took a particular style of karate for about 9 years. Then for other reasons I had to leave and I attended another martial arts class. It was a mixed bag of styles, but in my view it was effective combat. All in all. I like to punch things.
Don't we all?
That's why you wear gloves. Also, you don't need to be particularly strong for boxing, just need to be quick on your feet and have good hand-eye coordination (unless you actually want to knock someone out, in which case you're out of luck =P)
You gotta float like a butterfly and sting like a bee.
I'm pretty good at playing Ken in Street Fighter, does that count?
I took Five years of competition based Taekwondo (tournaments and such where I won) and later moved on to Taekwondo self defense in order to practice something a little more real and practical. I later quit and have not been in a class for months now.
I have a friend who takes a Brazilian Jiu-Jitsu class.
I do shotokan karate in a dojo near my house and I do aikido in school as a club.