Ashlee Simpson vomits at MisShapes'

Jessica and Ashlee Simpson invaded the MisShapes' dance party on Saturday reports Radar Online. Jessica , who slammed tabloid reports she is dating singer John Mayer and insists the two are just friends, was dateless ­while Ashlee was accompanied by Fall Out Boy bassist Pete Wentz, whom she proceeded to straddle, according to a fellow reveler.

Partying with an actual rock star apparently proved too much for young Ashlee, who had to excuse herself to vomit. Management kindly blocked off the bathroom to let her retch in peace ...