By assembling several major galleries in two massive warehouse buildings, Terrada Art Complex has rather successfully pursued their mission of "making Tennoz Isle into a hub of artistic culture." The complex is now an important stop on any contemporary art tour of Tokyo, and with so many diverse independent galleries, there's almost always something of interest going on.
In addition to more than 18 galleries in two buildings, there's also a nice cafe space on the ground floor and a tiny bar in an outbuilding. Check the website for individual gallery listings, or just show up and see what's on.
While you're in the neighborhood, the Kengo Kuma-designed art supply store Pigment is worth checking out as you explore the rest of the Tennoz area.