The Flaming Lips.
Giant confetti blasts, fog cannons, megaphones shooting fire, pink ninjas on the left, iron men on the right, giant santa claus and purple monster thing, gongs, insane video screen, nude chicks on stage during The Song Remains The Same, chanting, 90% of the crowd singing along while knowing every word, the greatest rendition of Taps in history, lights everywhere, space bubble, one lucky kid having hundreds of people singing happy birthday to him, a rousing encore of one of the best songs ever, and a surprisingly good view at Penn's Landing by the river.
Yeah, it was pretty good.