The two courts at NYSC Cobble Hill are open. Though last time I was there the net on the first court was down. I don't know how permanent a condition that is. I like that the last two posts I've made involve NYSC.
If you can bear the outdoors, you can go acroos the river to Jersey City on the Sphinx bus and there are a couple of courts out there that never got used in the entire time I lived there. And you don't need to get your NYC certificate or anything like that.