I see that the biggest energy fair, in central Wisconsin, is coming up in 2 weeks (June 19-21, 2009).
Midwest Renewable Energy Fair
They are planning another "Clean Energy Car Show"--last year there were homebuilts, new commercial electrics and hybrids, and older commercially built cars such as the ComutaCar. I have heard that this year should be even better. And of course, the rest of the fair has workshops, exhibits, and dealers with everything relating to renewable energy. Other energy fairs occur around the country, info here:
Rnewable Energy Fairs, Events, and Workshops
Energy fairs are a great place to learn about many aspects of renewable energy.