I have previously walked by this seemingly nameless, ramshackle restaurant and wondered what its deal is. A man I met outside today told me it's a kosher dairy restaurant by the name of Klein's. He said the owner used to operate out of a trailer on this little triangle bounded by Bedford Avenue, Keap Street, and Williamsburg Street West. The land, he told me, was owned by the Parks Department, but the restaurateur had been stationed there more than seven years when they came around to evict him, and there's some law that says that if you've occupied someone else's property that long, they can't kick you off.
That sounded like an urban legend to me, but, upon consultation with the internet, I think there may be something to it. In New York State, adverse possession requires ten years of continuous use (not seven, but not far from it), and this three-sided block is listed as a park on the Parks Department's website. I'd say this story warrants further investigation; wouldn't you? Somebody get me Geraldo Rivera!
(Did you know Geraldo was once married to one of Kurt Vonnegut's daughters? I just found this out!)