It's by Fleetwood Mac:
It's funny to watch Paul Rudd dance to this song in the 12-7-2013 episode.
Too bad that's not on YouTube,
Stashed in: Music Videos!, SNL
Sophie Ellis-Bextor - Murder On The Dance Floor
JS Bach - Cello Suite No. 1 - Prelude - VIsualized
Nathaniel Rateliff & The Night Sweats - S.O.B.