(Video link) So, it did happen, and it rocked! At last night’s 12-12-12 Concert for Sandy Relief, Sir Paul McCartney performed with Nirvana last night, backed up by Dave Grohl, Krist Novoselic, and Pat Smear. It was just as excellent as you’d hope it would be. Here is their new song, “Cut Me Some Slack.” The show might be over, but you can still donate to the Robin Hood Foundation at the concert’s site. (via Slate)