1. Santana at Woodstock, 1969 - Mescaline
Many artists claim that the drinks backstage at Woodstock were spiked with LSD. Roger Daltrey said he was tripping balls when the Who played their famous super-late-night set. But Carlos Santana was one of the many performers who wanted to be stoned at the show, and he made sure to arrive with some mescaline on hand. "When we first got there, around eleven in the morning, they told us we weren't going on until eight," he told Rolling Stone in 1989. "So I said, 'Hey, I think I'll take some psychedelics, and by the time I'm coming down, it'll be time to go onstage and I'll feel fine.' But when I was peaking around two o'clock, somebody said, 'If you don't go right now, you're not gonna go on.'"
He bravely took the stage and played an amazing set, though if you watch the video, it's a little obvious he's on something.