Let's Rock is a MxPxcompilation album of B-sides and unreleased material. "You Walk, I Run" was recorded by Jerry Finn during "the Ever Passing Moment" sessions, and "Make Up Your Mind" was also recorded by Finn and was released on "the Broken Bones" 7-inch. Both songs appeared on the "Responsibility" Australian import. The remaining ten tracks were previously unreleased and were self-produced. "Sweet Sweet Thing," an acoustic version here, was originally recorded with the entire band during the "Before Everything & After" sessions with Dave Jerden, then titled "Family Affair" and featuring slightly different lyrics. It was left off the album, although a portion of it can be heard in the album's "Before" and "After" tracks. Music videos were made for "Breathe Deep" and "Running Out of Time."