James Spader:
L7 - "Shitlist"
http://www.youtube.com/watch?v=AkmLpTXbNDQ

(change it up to Blacklist, the name of his show)

Andrew Rannells:
"I Love It" - Icona Pop
http://www.youtube.com/watch?v=UxxajLWwzqY

(When he and Hannah danced to this song on Girls, it really sent the song into the stratosphere http://www.youtube.com/watch?v=-qMplFDm_ZA)