Yeah, you wonder why they did THAT song and not one of their own. Ok, after Mike's speech no one was probably into "Fun, fun, fun", but why not "I get around" or something like that.
Anyway, a while ago I made a screenshot of probably this performance (by another youtube user, probably it was a TV report, I don't remember), because you have so much legend and talent in that one shot:
Bruce Springsteen, Brian Wilson, Carl Wilson, John Fogerty, Paul Shaffer and Mick Jagger