The Japanese probe IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) has apparently successfully deployed its solar sail, the first of its kind to actually be used in space. For details, see the articles on MSNBC's Cosmic Blog and Popular Science's website. For details on the exact workings of the craft, go to the IKAROS Project Page on the JAXA website.
You have to give JAXA (The Japanese Space Agency) a lot of credit. A few short years ago they were definitely a second-stringer as far as space capabilities go. But they began building up many of their capabilities, with probes to the Moon and a nearby asteroid and an ISS cargo ship. And now they've done something no one else ever has--successfully deployed a solar sail, something that previously only existed in the realm of science fiction.
In an age when most space agencies are either cutting back (like the US) or just trying to reinvent the wheel in order to catch up to the front runners (like China), its inspiring to see somebody actually try to forge ahead into new territory. I've always been a bit dubious about the long term practicality of solar sails in space exploration, but I'd be glad to be proven wrong if it turns out to be the case. No matter what, solar sails are just damned neat.
It will be a few weeks yet until anyone will be able to tell if the solar sail is working properly (with a light sail, momentum builds up very, very slowly over time, so its changes in momentum will be very hard to detect at first.) But here's hoping for the best.
Also, for people in the US, pay close attention. This is the kind of cool stuff that can happen when a national space agency isn't constantly having to reinvent itself every time a new president is elected (a problem going back practically to Nixon's administration), and long-term projects are allowed to actually come to fruition.
In the meantime, however, go Japan!