The Cassini spacecraft, which entered orbit around Saturn on June 30, 2004 has successfully observed and recorded and sent back all sorts of data about seasonal changes on Saturn, as the planet experienced its equinox. The main NASA / JPL Cassini site is here.
Last month, on August 11, sunlight reaching Saturn hit the planet's rings edge-on, essentially making them disappear in the planet's equinox. Saturn has two equinoxes, much like Earth, during each of its "years" or orbits around the Sun. Each orbit takes 10, 759 Earth days, or 29.7 Earth years, so catching this equinox was a pretty big deal. There's a good video here explaining, exactly, what's happening to cause the equinox.
Some of the most exciting data concerns new revelations about just how thick, and dense with ice and dust materials Saturn's rings are; some have peaks that are comparable to the height of Earth's Rocky mountains.
Perhaps the most stunning images were those captured at the height of Saturn's equinox, like the image above. Astronomer Phi Plait has by far the most easy to understand discussion of just what makes this so very very cool—and important. For those with broadband connections, the very very large, very detailed high resolution image of the picture above is here.