Larry and Laurie David dropped by to guest teach Prof. Sherman's UCLA class, "ENVIRON 188: Effective Methods of Social Change," which addresses the need for immediate action on the growing global warming crisis.

In an added twist, the couple also revealed the winner of the mtvU "Curb Global Warming" sweepstakes, handing the keys to Larry David's very own Toyota Prius - the hybrid car he drives on "Curb Your Enthusiasm" - to one lucky UCLA student. Watch it now on mtvU's Stand In.

• Watch the Larry David Stand In
• Help stop global warming now

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