Just moved to Brooklyn and am looking to find some people who want to get out of the city on weekends to climb outdoors or even just train indoors. Any recommendations for groups like this in the area?
I can't help you with the indoor Brooklyn side of things, but as far as outdoor climbing in the warmer months there is a place Rockland County called the Powerlinez. It has over a hundred single pitch routes of all levels. It has a fairly active facebook group with a bunch of people looking for climbing partners all the time. I'm planning to be there once a week when it warms up a bit. So definitely join the group and post a message. https://www.facebook.com/groups/110610805650592
EDIT: Forgot to mention, the Powerlinez also has hunderds of boulders and that's reallywhat it's known for. I don't boulder outdoors much so I didn't even think of it, but yeah, it's pretty good for that as well. You can find the whole area on mountain project.
You might have luck with the fb groups "Gunks Climbing Partners!" and "NYC Rock Climbing/Bouldering." The Gunks are world class trad of course, <2 hours from the city and pretty manageable by bus from Port Authority too. Cabs at the bus station in town can get you to the cliffs themselves, but its normally easy to hitch a ride from whatever Subaru plastered in BD and Petzl stickers is sitting outside the nearest coffee shop. Don't really know what the Powerlinez is like, though I've driven by a hundred or so times on the way to the Gunks and Catskills :) As far as I know, the best way to get on good sport climbs from NYC is to hop on a plane.
As far as gyms go, GP81 in Greenpoint BK is the place to be for bouldering and training, and the Cliffs at LIC in Queens is arguably the best gym for tr/lead in the area. Both are good places to find partners.
Just be careful who you go outside with of course. The Gunks is full of 5.11 gym climbers having full-on life-threatening epics on 5.6, and most good weather weekends involve a carryout of an injured climber, so be careful out there.