Cosmos-1 will be the first spacecraft to use solar sails rather than an engine for propulsion, and although this is a very funky technology, what I find most interesting about this is that it appears to be an entirely privately funded operation, by the Planetary Society. It looks like the era of private spaceflight and exploration may be about to dawn.
The flight isn't going to be particular ambitious – just orbiting the earth before (probably) decaying and burning up in the atmosphere, but it will be a proof of concept which I find very exciting. Combining it with giant orbital lasers to provide continuous thrust in the outer parts of the solar system is the next step! :-D.