Two new contests have been announced. The first is BrickArms' 'Last Stand' Contest. The challenge is to create a 32x32 (or larger) scene of "a small group making a valiant last struggle against a much larger force". The prize pool is quite nice with accessories in rare colors, prototypes, and printed minifigs all up for grabs. You can see the full details and rules on the BrickArms' forums.
The second contest comes from a site I just found out about! VignetteBricks is hosting a 'Murderous Minifigs' contest. The objective is to create an 8x8 vignette depicting either a classic scene from the game 'Clue', or a riff off of the classic concept. This could really be a lot of fun! The title of 'King of Vigs' is up for grabs...that and some loot, of course. You can see all the details on VignetteBricks.