Time's Most Influential People in the World

11 of 14: Actor Matt Damon, 40, joined Gary White, 48, an expert in water-supply systens and created the nonprofit Water.org in 2009 to help get clean water to those who need it. Damon is also the founder of the H20 Africa Foundation, a co-founder of Not On Our Watch, a spokesperson for Feeding America and a board member of Tonic Mailstopper.

"Being a celebrity is like being a 5-year-old in a room with all the adults staring at you. It's easy to spin out of control. But if you redirect the energy coming at you to a cause you care about, it can be very powerful," actor Ted Danson wrote in Time.

(Pictured: Matt Damon appears in a still from his 2007 film, 'Ocean's Thirteen.') ( Photo / Warner Bros. Entertainment)