Willie Nelson is one of the elder statesmen of American roots music and the father of the “outlaw movement” which developed as a way to keep a pure branch of country music alive when it first started turning pop in the 60’s and 70’s. Despite his age — he’s now 75 — Nelson has remained remarkably active both musically and politically; he’s best known for Farm Aid and “On The Road Again,” but more recent projects have included biodiesel activism and a cover of the Dave Matthews tune “Gravedigger.”