Not sure if this is what you're looking for in the bar/club setting, but there's a long and angsty SPN Big Bang that has Massive Issues Jared, running from a troubled past, working as a bartender. His boss, Tom Welling, sends him to a "flair" bartending class taught by Jensen. There's several bars and clubs, lots of dancing, and a bazillion supporting CW cast. Non-con warnings (not partner betrayal). Supporting cast also includes Sandy, Mike, Chris and/or Steve, Chad, Danneel, and Michael Weatherly, not all of whom are entirely nice but some of whom are.

Again, if you're looking for the boys simply out for a night of fun and dancing, this is not the droid you're looking for.

"A Lesson a Day (Could Kill You)" by Lycaness

<http://lycaness.livejournal.com/12654.html> is the master post.