253 Mathilde is the largest asteroid that has ever been visited by a spacecraft. It's held that distinction for more than twelve years, but next year it'll be upstaged by the considerably larger 21 Lutetia, which Rosetta will fly by on July 10.
Dawn entered the main asteroid belt on November 13. As it ventures ever deeper into this vast collection of material between Mars and Jupiter, it may be tempting to think of the spacecraft constantly dodging asteroids.
The two big things happening this month are the launch of the Wide-field Infrared Survey Explorer (WISE), from Vandenberg Air Force Base no earlier than December 9 at 06:09 PST (15:09 UTC), and the December meeting of the American Geophysical Union (AGU) from the 14th through the 18th.