I can take no credit for the originality of these ideas. While perusing Wes Modes' adventure website (one of the few I've been able to find) I stumbled across the idea of "Punk Rafting". Basically it goes like this: a group of friends takes a rickety old pick up truck to a river destination of their choice. They arrive, scout out a landing, and spend a few days gathering junk that will, when put together, float them down the river. They then assemble a raft and Huckleberry Fin their way down the river.
Sounds like one hell of an idea to me! So two of my friends and I will set out this fall to attempt our own Punk Rafting adventure!