Feeling groovy? You’d better be — the musical acts on Tuesday’s late-night TV scene clearly were. Up above: Captivatingly unique singer-songwtier Mosey Sumney, finally making his long-overdue tube debut with the tune Cut Me from his upcoming double album græ. Down below, Skip Marley and H.E.R. try to convert The Tonight Show Starring Jimmy Fallon into a dancehall club with their number Slow Down. Good luck with that, you two crazy kids. As for the rest of you, get in the groove before it’s too late.