Here's an entry from the "just plain cool" department: an animation of 20 recent Cassini images, watching Mimas occult Prometheus as the shadowed face of the rings moves across the background. Cassini takes these "mutual event" movies mostly to refine the precision of orbital information of the various bodies. But I like to think that they also get just a little bit of priority because they look so cool.
NASA / JPL / SSI / animation by Emily Lakdawalla
Mimas, Prometheus, and the rings in motion
Cassini took the 20 images that make up this animation on October 20, 2008. Cassini stayed pointed at Mimas, the innermost of Saturn's round moons, as the vast ring system (mostly the A and F rings) swept through the field of view; also crossing the frame is the inner shepherd of the F ring, potato-shaped Prometheus. At the time, Cassini was positioned slightly above the plane of the rings; since it's late winter in Saturn's northern hemisphere, Cassini is looking onto the shadowed side of the rings, while Mimas and Prometheus are fully lit by the Sun. In some of the frames, a faint wisp of a stream of material drawn out from the F ring by Prometheus is visible. Click here to download the full-resolution version (animated GIF, 2.25 MB).