Enceladus

Enceladus is cold - a moon of ice. The hi-res mosaic of 21 images from Cassini is amazing. Here is a movie of Cassini's close approach (109 miles) that's not too bad.

Enceladus is the source of Saturn's E ring.

Enceladus is only 310 miles in diameter.

Enceladus' south pole is as much as 50 degrees warmer than its equatorial region.

Enceladus is the smallest body so far found that seems to have active volcanism.