HALLOWEEN CLASSIC: If you’re looking to escape the barrage of skanks dressed up as sexy nurses, sexy pirates, sexy schoolgirls, sexy bumblebees, or sexy skanks, your best bit might be the midnight showing of “The Rocky Horror Picture Show” at the Music Box. 3733 N. Southport Ave.; Lakeview. Midnight. $10.50.
HALLOWEEN NOIZE: The smooth-talking duo in Chromeo teams up with the noisy electro-punks in Crystal Castles and Boysnoize to present what should be a crazy pre-Halloween dance party at the Congress Theater. And in the spirit of Halloween, tickets include some treats, like a one year subscription to TimeOut Chicago, oddly enough. 2135 N. Milwaukee Ave.; Logan Square. 7 p.m. Sold out. 17 and older.
HALLOWEEN NERD-GASM: The Chicago Nerd Social Club presents Nerd-O-Ween, a costume contest that includes four categories: best overall costume, nerdiest costume, silliest costume, and most unique costume. (How can something be “most unique” when it’s already one of a kind? Come on, nerds.) Flounders Bar And Grill, 2201 N. Clybourn Ave.; Lincoln Park. 7 p.m. $10 in advance or $12 at the door.