I think I did this a while ago on one of my group websites, and it's actually kind of fun!
Basically, the premise is:
Person 1: ADGH
Person 2: A Darn Good Heart, HANM
Person 3: How About No Man, FGLKJB
etc etc,
It's really simple, just make up what the acronym means, and then make your own for the next person!
Just try not to make anything inappropriate of course, as well as try not to make them very long! They become really difficult otherwise. I'll start you all off!
BMVAT