it means grateful dead family, and half those people never even saw the grateful dead. i don't trust those guys.
Every time I found acid at a show there was a section in the parking lot where people were crowded in real tight. Underneath the murmur of conversations, bongos, and music from car stereos you could hear certain individuals saying almost as a chant 'doses, rolls, molly, shrooms, chocolates'. Talk to one of them. If you're having trouble getting some one talk to you, make sure to wear something psychedelic or walk around laughing with a few other people.