In honor of the four new pieces of Grammy hardware they received tonight, and a career spent maintaining their "indie cred" (so says Jack Black) the Foo Fighters got to perform "Walk" from a crowded tent adjacent to the Staples Center. Because everyone has a different idea of what "tribute" means. On a song they've been pimping since Wasting Light's release last year, Dave Grohl was extra screamy, saving the guttural pleas for mid-chorus while hair fell over his eyes in all the right ways. Blundering guitar chords on top of guitar chords gave way to participatory clapping, the ultimate reward for those who've camped outside the big show. If you're already a fan of the Foo this should serve to prove how much they can still seriously rawk a stage, whether its in a 50,000-seat area or next to a beer tent. But if not, this might not be the one to win you over.