Video: Lady GaGa, Beyonce and More Rock 'American Idol' Finale

Lady GaGa and Beyonce Knowles, who served as guest mentors on a previous separate week of "American Idol", were two of the many musical guests at the finale of the singing competition on May 25. The former was bathed in blue lights as she performed "The Edge of Glory", while the latter belted out a live version of "1+1" with red lights and smoke surrounding her. Appearing high at...