What does it take to make green cool? When it comes to green cars, we can guess that GM might be interested in figuring out an answer to this question. Later today, GM will bring together Marissa Brassfield from Trendhunter.com, John Waraniak from SEMA and Adam Bernard, who works on competitive intelligence and trends for The General, to discuss the issue. Framed by two recent events, The Business of Plugging In and SEMA, the Q&A will go over "some very real trends emerging for green vehicles" and whatever else participants want to throw in. The chat happens this afternoon at 2 p.m. EST and you can participate by clicking here.