Collect Dumbo, Artlog and Brooklyn Arts Council's themed art walk/party around Dumbo isn't actually free, but for $15 there's an awful lot of parties, art and booze to be had. Details and tickets here.
Matt Miller's abstract constructions and canvases at John Frum Foundation, 66-68 Washington Ave, Suite 2 (at Park Ave), 5-8pm
Group show of collage artists Collage: Collage at NURTUREart, 910 Grand St (between Olive and Catherine Sts), 7-9pm
Jason Horvath's surreal furniture design at Eastern District, 43 Bogart St (at Moore St), 7-10pm