8. Umphrey's McGee
Jam bands and prog groups have some of the most passionate fans in music. This six-piece from Indiana offers a perfect combination of the two genres, meaning they have a die-hard cult of supporters that allows them to play huge venues like Red Rocks even though most people have never heard of them. The unconverted simply need to see them live: Their Live at the Beacon Theater LP contains jaw-dropping renditions of "Where Is My Mind" by the Pixies and "Layla" by Derek and the Dominos.