I only started climbing because my brother recommended it after the hockey class didn't work for me schedule-wise, but it's fun :) It's also very helpful to have a trainer who explains basic techniques etc. I could use a lot of strength training, especially for the arms, but laziness is a problem. (Doesn't help that I have to be careful or my wrists start hurting.)

Thanks for the vid links! Climbing on buildings also looks very impressive, but I'll stick to halls ^^