First, throw out any expectation of ownership or launching a company from this exercise. Once you get rid of those expectations you can really have fun. I was under the misconception people really wanted to build something in the one I attended. We actually won the competition but it turned out the two biz dev guys were testing the waters for their concept and just wanted to have a team put an in depth presentation / demo together for them. After we won I thought we had a viable start up and thought we'd get rolling. Instead, the two biz dev guys went their way and didn't even tell the group they were pitching it elsewhere. Since the rest of the group were just kinda helping out on the weekend, hey had no expectations really so it died out.
Just set your expectations first. Maybe even discuss it with the group.