Caught in the Act

Inside Robert Downey Jr.'s Belated Birthday Bash

04/14/2011 at 10:00 AM EDT

Paul McCartney chatted up the staff at the Apple store at West Hollywood's The Grove, asking questions about the merchandise before buying a MacBook Pro. The rocker was sporting mirrored shades and, according to an onlooker, "seemed cheery and eager to learn" about his new computer.