Last night on Saturday Night Live, Sir Paul McCartney and the surviving members of Nirvana performed their new track, "Cut Me Some Slack," for the second time in four days. The collective, which features McCartney, Dave Grohl, Krist Novoselic and Pat Smear ("Sirvana," anyone?), debuted the song last Wednesday night at the 12.12.12 Concert for Sandy Relief at New York's Madison Square Garden.