Looks like Krishnas to me. The two bald guys are playing the harmonium or shruti box, which makes a droning sound. Anoying as hell, kind of like a bagpipe. The hippie chick with the drum and her half-in-frame cowboyfriend just happened by and started jammin'. They were on their way to Occupy Wall Street but got distracted. She's hoping they'll do a Dave Matthews song next.
The standing horn guy is also making a droning "lonely trumpet" sound mixed with some snake charmer riffs. Leslie Nielson needs to punch the whole lot of them the fuck out.

My favorite is the guy on the bench behind them. The only actual South Asian in the park just shaking his head and thinkg wtf.