Paul Simon welcomed Grateful Dead co-founder Bob Weir during his Sunday night (August 11th) performance at San Francisco's Outside Lands Festival. Together, the '60s icons performed a rough and under-rehearsed version of Simon & Garfunkel's 1969 classic, "The Boxer," marking the first time the pair ever appeared on stage together. reported Simon recalled to the crowd first meeting Weir when he knocked on door of the Grateful Dead's legendary house and headquarters in Haight-Ashbury when both Simon & Garfunkel and the Dead were booked to play 1967's Monterey International Pop Festival, .

Simon named the San Francisco Parks Alliance and Friends of the Urban Forest as the recipients of all net proceeds from his August 11th headlining set at the festival.

Paul Simon is booked to play tonight and Wednesday (August 13th and 14th) in Maui, Hawaii at the Maui Arts & Cultural Center. Although he's retired from touring, Simon had said prior to launching his farewell trek last year that he intended to continue to sporadically perform and donate the proceeds to charity -- preferably those focused on the environment.

Simon admitted that during his performances, he needs to feel the freedom of going where the music takes him -- rather than just imitating his studio tracks: "What happens is, I work on the music as I'm performing and I change arrangements and the music evolves and the band becomes more of a unit. And there's a process of growth and evolution and it's very interesting. Then at a certain point you sort of solve all the problems. The danger is that you just start to repeat yourself automatically, and then its less interesting. And at that point I feel that I'm doing an imitation of myself."