Talk about cramming for a test: Student teams from 20 colleges will have just ten days to assemble solar-powered houses before putting them through their paces in the biannual Solar Decathlon. Instead of discus and hurdles, the ten events will assess qualities like curb appeal and temperature control. Homes, like the 2005 entry above, will be open to the public October 12-20 on the National Mall in Washington, D.C. Too far to trek? Find local green homes to visit at nationalsolartour.org.
(Photograph by Stefano Paltera/Solar Decathlon)