I speculated about a couple possible opponents for Michigan in their proposed outdoor game in 2010--Notre Dame still intrigues me--but Michigan went with the safe route and chose Michigan State as an opponent for an outdoor game on December 11, 2010.

I'd assume Michigan had MSU in mind all along since they have a series with MSU scheduled for December 10-11 that season. They are still awaiting approval from the CCHA. If the game sells out, not only would it break the world record for hockey attendance, it would be the first game with over 100,000 fans in attendance.