The magic of the Waybacks' annual set is the mystery. One of the most anticipated performances of the festival, the California-based band presents a classic album every year. Only nobody knows in advance which one. Speculation overtakes social media and lawn chair conversations around the festival. What will the album be? Turns out MerleFest isn't the only birthday boy. The Beatles' Sgt. Pepper's Lonely Hearts Club Band turns 50 this year and, with the help of Sam Bush, Lauderdale and banjoist Jens Kruger, the Waybacks delivered an inventive tribute studded with sounds that spanned the psychedelic era.