I never realy liked gravity bongs all that much. It's kind of a cool concept in a way, but in practice it's kind of a pain in the ass. Also, I don't need massive rips to get the job done. I'd rather take a few smaller hits, take a little air with each one, spare my lungs and get just as high as I want. And I agree with the OP that it's a bit more social to pass around a pipe or a bong than it is to set up a gravity hit for each person. The first person will be totally unconscious by the time the last person gets his hit.