We sent a whole bus load of kids down from UNECOM last year, and i've got to say that it was pretty fun. We met with staff from both of Maine's senators and congressmen (our out-of-state classmates met with those from their homestates), and then hung out in DC. I got the worst blisters I've ever had from walking around (in april! in open toed shoes! and short sleeves!), but I really had a great time.
The maine osteopathic association, I believe, paid for the whole thing. It was a long bus ride, but I think a very good experience.