Willie Nelson is a Founding Member of the Green Music Group, which is affiliated with Reverb, the non-profit organization founded in 2004 by Guster’s Adam Gardner and his wife, environmentalist Lauren Sullivan. This summer the Green Music Group is initiating a number of challenges and anyone who participates is entered into a drawing to win a Honda Insight Hybrid. The current challenge (which concludes on Friday June 4 at noon ET) is “to find a more earth-friendly way to travel to work, school, his show.” The details are available at the Green Music Group site and the grand prize for this weekly challenge is a $500 Gift certificate from Hard Rock.