When I went to Oshkosh this year, one of the coolest things I saw was the plans built pedal planes. They make a new design every year, and there is even a Pietenpol design (how tasteful of them... :)

These are fairly popular in EAA circles; here is an article on why you should build one, here is the source for the best plans, and here is some good pictures of what they look like.

Oh, and you can read about the designers here.

Hmmm, if I could scale up the GeeBee large enough to put me in it....