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
Pharrell Williams - "Happy" Tribute videos
Tiny Dancer Who Am I Deal With It gif
Low Tech 3D Projection Mapping | Avicii Wake Me Up
Giving up: 40% women, 28% men, 39% youth don't want a job