Definitely man. I like to smoke before going for a run because then I go off in my own little world listening to my music, and before I know it I've run further than I intended. Never a bad thing!
I also like to get a little stoned before BJJ. If you do this though, be careful, because one time I got a little toooo stoned, and struggled with my co-ordination when learning techniques. A little buzz, nothing too crazy, and it makes rolling an incredible experience!
i got tooooo stoned one time at BJJ and tapped when somebody got mount haha i was in no danger waht so ever i was just so high that i thought i was going to die.