There are lot of cool creative spaces in the Gowanus area; Powerhouse Arts is one of the biggest and best!
Powerhouse Arts (PHA) is a not-for-profit organization committed to creative expression.
https://powerhousearts.org/
It's an amazing (and enormous) space with a considerable array of impressive facilities, from ceramics and print studios, to large-scale fabrication labs. Also a very cool history — former transit power plant with a lot of money poured in to restore it.
They host classes, which I haven't yet taken, and occasionally big public events. We went for a recent "community day" and it was great, with lots of arts displays and family-friendly activities!
Other local arts spaces on my list to explore:
𝔊 Brooklyn Glass 𝔊 Craftsman Ave 𝔊 Makeville Studio 𝔊 Gowanus Darkdoom 𝔊 Third Avenue Clay 𝔊