Katy Perry, John Mayer, Kat Graham, and others stop by the Universal Music Group After Party at the Ace Hotel; Pharrell Williams, Stevie Nicks, Les Moones, Smokey Robinson, and other industry insiders attend Sony Music Group's Post-Grammy Reception; Nile Rodgers performs for Kate Beckinsale, Chris Martin, Miles Teller, and many more at Warner Music Group's late night celebration—take a peek inside all the top festivities that followed the big show in this Grammy after parties roundup.