Because, in something that is apparently rarely done at Studio 8H, they played a mini-concert for the audience. Making up the front row of the 3-song set was Seth Meyers, Amy Poehler, Fred Armisen, Bill Hader and Andy Samberg, all looking absolutely transfixed by this band. The Fire has some high-powered fans, for sure, and converted a good chunk of the audience last night as well.
It's odd that my highlight of the show happened off-camera-- at the end of their three-song set, they played "Wake Up", off the stage and in the audience. Amazing. The cameras were rolling, I'm hoping this appears somewhere.
Also a funny tidbit: Five seconds before the show went back live for Arcade Fire's second song, Rainn Wilson looked at lead singer Win Butler and, in a very deadpan voice, asked what happened to his guitar (he had smashed it during their first song). Ha.