Multi-Grammy-winning singer/songwriter John Mayer is raising funds for the Northern California Institute for Research and Education (NCIRE), one of the nation’s foremost organizations studying the effects of war on U.S. military personnel.Mayer partnered with the organization in 2011 on several pilot programs aimed at helping veterans overcome the effects of post traumatic stress and lead healthy productive lives as civilians.To raise the funds, Mayer has created a unique opportunity for fans that not only rewards the winners of an online raffle, but also helps educate fans on post traumatic stress and the need to help active military when they return home. Three winners will be chosen to spend a day with Mayer in the coming months, working together on a day-long volunteer project to help veterans. Raffle winners will work side-by-side with Mayer and veterans on the project and celebrate the completion of the project with a meal and photo session.Mayer’s programs with NCIRE include a Veterans Exercise and Wellness Program, Integrative Medicine for Traumatic Stress, Women Warriors Fitness and Nutrition Program and Military Acculturation Program. All four programs are based in the San Francisco Bay-area with hopes to replicate them in other parts of the country. Mayer first became interested in veterans issues following a visit to Camp Lejeune five years ago, and was honored by the Recording Academy earlier this year at its annual Grammys on the Hill event for his work on behalf of veterans.For more information on the raffle, click here. Entry deadline is November 1.