YouTube amazes me sometimes. Here’s Crosby Stills & Nash’s coming-out party at Woodstock in 1969, singing “Suite Judy Blue Eyes.”

A word to the unwary: if you want to get the original CSN album, either avoid the one which includes bonus tracks or don’t listen to the demo track of “Teach Your Children;” keep your memory of the version which appeared on “Deja Vu” unblemished. Or click here to see and hear it done live after they’d figured out the harmonies.