Did some kickboxing in High School as one of the general after-school activities (mostly sports) they had for us. It was pretty fun, but it wasn't intensive enough for it to really make much difference or give much skill. I still understand at least the theory behind throwing a decent punch and stuff though.

My boy Michael was doing the classes with me and he smurfed his knee up with some kick, and it bothered him for years. It still might, I'll have to ask him next time I see him. I wasn't about to go alone because smurfing around with my best friend was the only thing that made school tolerable, so we just skived off and went to my place to play videogames whenever we were meant to be in class.