I was lucky enough to meet a conspirator within the Graffiti Research Lab whilst in NY, who suggested I check out 5ptz in Long Island City, Queens. I took the 7 train out to check it out, and quickly realized where it was as I passed by on the elevated train line
5ptz is supposedly the largest graffiti gallery in the world. It is all done legally, but to do a piece you have to obtain a permit, and then it only lasts for a year before it gets covered. This means the quality is generally amazing, artists from across the globe come to throw up pieces. The building is entirely covered, and takes up a whole city block. Inside are a bunch of artist work spaces not affiliated with the graffiti space. It all reminded me of Tacheles in Berlin, only a lot less commodified
There are a bunch of videos on 5ptz on youtube, but check the short doco here
P.S. 1 is located directly across the road, an old elementary school reconverted in to a gallery for installation art. Sadly there were no installations in the large outdoor spaces while I was there, though the "WACK! Art and the Feminist Revolution" exhibition was on that had recently been in L.A.