From the official website:

The 3rd Annual 72 Hour Film Shootout! is a National Competition where teams will have 72 hours to write, edit, shoot, and produce a 6 minute short film. This year's competition is happening June 9-12, 2006!

Le Grand Prize:
A chance to create an MTV World Promo!
Cash money in the form of $1000

Second Prize
$750

Third Prize
$500

Top 3 winners:
1 on 1 pitch sessions with MTV industry executives!