Somewhere on the Upper West Side, Yoko was smiling as son Sean (looking freakishly like Dad) and Rufus Wainwright (musical progenies apparently roll together) played a cover of Madonna's 1985 hit "Material Girl" to the folks at Occupy Wall Street on Sunday. Clever. Fun. Joined by a banjo and Lennon's girlfriend, model Charlotte Kemp Muhl, on an accordion, giving the song an extra boost of singalong appeal. I suppose they wouldn't know anything about this, huh?