The GRAMMY Foundation and MusiCares have teamed up for a back-to-school auction via eBay. Music fans will find up for bids one of a kind collectibles like photos and original artwork from Paris Hilton and Taylor Swift, signed postcards from Lil Wayne and Kanye West, signed guitars from John Mayer, Depeche Mode, Tom Petty and more. Dave Grohl and the Jonas Brothers have also donated signed Rock Bands for Xbox. The auction runs through July 31st. For details visit Ebay.com/Grammy.