Hurry to catch one of the best shows all year which closes April 1: the NYU Grey Art Gallery show, Inventing Downtown.  Focusing on artist-run galleries of the sixties, the show is both nostalgic and forward thinking, the art, though smaller scaled than today, seems very contemporary.  What shines through: the collegiality of the art world, the kindness with which artists treated each other, the playful, pick-ourselves-up-by-our-bootstraps, can-do mentality.  What is sad: so many talented people utterly forgotten by the history books. Many of us do know Red Grooms from his seventies era large scale installations, but here we see his do-it-yourself beginnings.