A brand new “DIY done-right” venue, as booker Nelson Antonio Espinal calls it, has been operating (at half-capacity anyway) in the J train’s shadow these past few weeks, while most of us probably had no idea. The secretive new operation, aptly called The Gateway, is located just off the Gates Avenue stop on the Bed-Stuy side of Broadway. Late nights, it’s pretty quiet around here, save for a Crown Chicken knockoff, a newish vegan diner called Toad Style, and the twice-a-weekend shows at Bohemian Grove, just north on the Bushwick side of the border.