Add yet another U.S. city to U2’s ambitious PopMart Tour: Springfield. Following in the footsteps of such past musical guest stars as the Smashing Pumpkins, Sting, and Tony Bennett, the Irish rockers will likely lend their voices to the 200th episode of Fox’s The Simpsons, which airs next May. Homer runs for the office of sanitation commissioner and tries to rock the vote by campaigning at a U2 concert. ”Knowing U2’s strong political consciousness and Americans’ passionate feelings about weekly trash pickup, it seems like the perfect match,” says Simpsons exec producer Mike Scully. Hey, where’s the cameo by Garbage?