But it's really a couple-times-a-year thing, so don't get too excited, and you have to get some good shit and take a huge hit (like a 2 liter bottle). Though pretty much all of my friends say that the highest they've been was also with a gravity bong, so it probably won't dissapoint.
DUDE! Ive just searched for gravity bong. We call them turbos in England. Buddy, I smash them all the time! Seriously. Use them in a bath, bucket, sink, always with a 2 litre bottle. I use an old whisky bottle as its real sturdy and easy to clean. I do like them. I'm just not keen on the coughing that follows a hit from these beasts.