A very rare thing in skateboarding, rollerblading and BMX. It is like a halfpipe except it goes all the way around, so you're not getting any tricks off this baby, your going upside down. Tony Hawk once rode a fullpipe, getting a ton of speed then going all the way round, though most others before him couldn't even get to the upside down bit (luckily for them). I am unsure whether it has been done by rollerbladers or BMXers, but it probably has.