Collaborations continue on the Last Summer on Earth Tour. As previously reported, the outing features Barenaked Ladies, Cracker, Blues Traveler and Big Head Todd & the Monsters. On Thursday at Council Bluffs, IA’s Stir Cove, Barenaked Ladies singer Ed Robertson emerged during Blues Traveler’s set for a cover of Peter Gabriel’s “Sledgehammer.” The package tour rolls into Philadelphia, PA’s Festival Pier this evening.