Check out Washington Square Park, Its in SoHo (The East Village) SoHo stands for "South Of Houston" (Pronounced House-ton) aka Greenwich Village.

There ought to ge something going on in Central Park,on The Great Lawn somewhere.

Or I'd bet at the Lennon Moasic Memorial (71st and Central Park West) In Fact this is where I would check first!!

Tompkins Square Park,also in The Village,would be a good bet too!