I've been wracking my brain trying to remember. In TOS we had Beyond Antares, space hippies, Riley's Irish ballad. In TNG we had Klingon opera (and probably more but I'm a bit rusty on TNG). In VOY we had the EMH singing a lot and 7 of 9 singing a little. In DS9 we had a whole singing character in Vic Fontaine. Was there any singing in ENT? By anyone?