via Mrs. Espresso
See the dollar bills under Mr. Espresso's suspenders?
Except I've slowly started to change my mind. I think the idea that it gives you the chance to dance with someone that otherwise you may not have the opportunity to, is what did it for me. And since it's encouraged for people to cut in, you could dance with far more people in a given time than you would otherwise.
via Mrs. Lioness
Mrs. Lioness dancing with all her bridesmaids.
via Mrs. Ballet Flat
I can't imagine this guest was contributing his own money.
As for what song, I think it'd be fun to use "That's What Friends Are For," which reminds me not just of Bar & Bat Mitzvahs I attended, but even more importantly The OC's Chrismukkah Bar Mitzvah Spectacular. I think it's a great fit since it's an easy song to dance to, plus in my opinion, the whole point of the money dance is to be able to dance with your friends that are there to celebrate with you.
Are you familiar with money dances? Would you ever consider having one (or did you have one) at your wedding?