Justin Timberlake and Justin Bieber had very different Sunday nights. When JT wasn’t performing at the Grammys, he was sitting with his wife, Jessica Biel, plus Beyoncé and Jay-Z. When JB wasn’t being completely Grammy-snubbed, he was venting serious frustration over on Twitter (all just 24 hours after hosting SNL). And yet both Justins wound up in the same spot, releasing late-night tracks in hopes of launching late-night dance parties. Timberlake’s “Mirrors,†off his forthcoming record The 20/20 Experience, is an eight-minute mega change-up from “Suit & Tie.†Bieber’s jam is a “not finished song im working on :)†called “You Want Me.†And he raps on it.