Time for a summer sing-along, but forget the bonfire! Instead, gather around the cool light of your TV to watch the man who wrote or made famous most of the songs they taught you sing at camp. Tonight on PBS, Great Performances presents Pete Seeger's 90th Birthday concert at Madison Square Garden.

Joan Baez (who you can watch boogie down during "This Land is Our Land"), The Boss and The Grouch (Oscar, that is) were all there, as were Billy Bragg, Bela Fleck and Dar Williams, among many others.

Proceeds of the May 3rd concert went to the Hudson River Sloop Clearwater, an organization Seeger, an "avid" environmentalist, created to help protect the Hudson River.

American Masters produced the only authorized biography on Seeger in 2008. Click here to watch a younger Seeger perform "'This Little Light of Mine."