The Mars Society has updated its University Rover Challenge site in anticipation of the 2008 event. They will be offering "transportation, lodging and admission for 5 team members to the11th Annual International Mars Society Convention in Boulder, CO in August, 2008, and large cash prizes".
Draft rules and a video for the challenge have also been posted. There are challenges in several categories that the rover needs to meet: Geology, Biology, delivery of emergency supplies to a simulated distressed astronaut, and construction.