Say It Ain't So by Weezer (Letterman, 1995)

Unfortunately for Weezer's Letterman debut, Rivers Cuomo had just had surgery to extend one of his legs 2" to match the other one. He was having a bit of an existential crisis while he was enrolled at Harvard, wondering if being a rock star was for him. This was also when he was in the process of writing Weezer's second album "Pinkerton," which focuses heavily on his personal crisis with both his career choice and personal romantic life.

During the performance, you can see Rivers is standing quite still, and that's because his leg is in a brace under his pants. Before the show, Rivers reportedly asked his band members to move around a lot and make a scene so hopefully people wouldn't focus on him. Matt Sharp clearly cranked it up to 11 during the performance and helped to save the day.

The result is a classic performance.