Yeah Yeah Yeahs' new single had a week of high profile TV appearances: Jools Holland (4/7), SNL (4/11), and Letterman (4/14). The band switched things up for Jimmy Fallon last night, promoting dancefloor violence with the Gayfish-approved "Heads Will Roll." This meant David Pajo on bass for a change, and a younger, head-bopping studio audience. Karen's still a happy camper. ...