Vince Vaughn is back to doing what he does best ... comedy!

His opening line in the new trailer for Ron Howard's The Dilemma is classic. Vaughn says, "Ladies and gentlemen, electric cars are gay."

The movie focuses around Vaughn, who catches his best friend's wife cheating ... and he's left with the dilemma as to whether or not he blows the whistle. Also starring in the film, Kevin James, who plays Vaughn's co-worker and best friend. Jennifer Connelly and Winona Ryder star as their wives ... while Channing Tatum plays the "other man."

The casting sounds delicious. Dilemma hits theaters January 2011 ... and we can't wait!