The Imagine Cup Visual Gaming is a student game design competition. Competitors are challenged to program a 3d video game using an SDK provided by Microsoft (teams of two allowed). Entrance in the competition is free. Prizing for the competition includes an internship with Gas Powered Games (The makers of Dungeon Siege II!), an $8000 grand prize, free copies of Dungeon Siege II, and a trip to Yokohama Japan. First deadline: March 1st.
As for the Rendering Competition, competitors are challenged to tell a story in 3d. Students can collaborate with up to 3 teammates to create the best real time rendering coded in DirectX9 and Visual Studio .NET. Everyone who registers to compete gets a free copy of Microsoft Visual Studio .NET. The grand prize for the competition is $8000, and the winners will be flown to the awards ceremony in Yokohama Japan.
More info can be found here.