On many big events and holidays I create lists to point out and suggest some cool places to go in that area or the city for that event. These lists over the years include Halloween, New Year's Eve, St Patrick's Day, etc. I won't be doing it anymore for Mardi Gras.
It's this simple the closest thing we have to Mardi Gras is the West Indian Carnival, and really its the J'Ouvert the night before. J'ouvert is where people go down the street with the Steel Panners on Flatbush Ave from Eastern Parkway to Empire Boulevard dancing, drinking, parading, having mud thrown on them, etc from 2am-8am in the morning and leading to the parade the next day. It's truly magical and something you should experience once.
With that said this stufff at the regular bars, it's whack. There's no vibe, there's not open loss of inhibition, its fake beads with no real cultural understanding, its not genuine and to be honest not even all that fun.
So if you're out tonight just go to your usual standby bar, don't do anything with a Mardi Gras theme unless its close friends. Just trying to look out for ya.