yea its def cool looking at BMX style tricks on a fixed but it can't be good to the frame with long term usage. i'd say its prob best and safe to keep all wheels on the ground when doing tricks on a fixed, no in the air business if you want your bike to last a long time
* also seems there def is a limited # of tricks to be done on a fixed which will sooner or later just be boring to watch after a while (Carnival). Gimme some helmet-cam riding footage riding the waves of traffic and that's where its at for me.