Lots of pop stars lip-sync live, and sometimes they get caught doing it. Ashlee Simpson had the unfortunate luck of being found out while performing for millions of viewers on "Saturday Night Live." It started out OK: Ashlee made it through "Pieces of Me" without a hitch. But when she was supposed to perform her second song, "Autobiography," the "Pieces of Me" vocals started playing again, and "Ashlee" started singing before her lips hit the mic. Flustered, she started dancing a jig (the obvious reaction) and walked offstage. Ashlee's excuse for lip-syncing? Acid reflux.