Sparkfun has posted rules, walkthrough video, registration for the 2013 AVC.
Both air and ground competitions should be really interesting. The ground course is slightly shorter than previous years, and features fixed, known locations for barrels, the bonus hoop, and the ramp (my robot Data Bus is going to to *love* that feature)
Air competition is primarily over water! And features a wicket hoop thingy to fly under for a bonus, required autonomous takeoff, and a bonus autonomous tennis ball drop.
Scoring is points based with a starting pool of points to which bonus points are added, and time (seconds) is subtracted.