Oct 31 @ 8 p.m. Webster Hall turns into Webster HELL for the official post-parade after party. All four floors will be filled with sexy monsters and freakish ghouls (and probably some Michael Phelps swimsuit costumes thrown in for good measure). The night's best get-up nabs a $5,000 prize (!!!), awarded at 2 a.m. Open bar: 8-10pm. Price: $25 entry; 19 to enter, 21 to drink.

Webster Hall - 125 East 11th Street (btw 3 & 4 Ave), 212-353-1600

Oct 31 @ 9pm - 4am. The Dutch DJ Armin van Buuren spins up a spooky soup of big beats for all Halloween dance freaks. Dress to impress (that means in costume). And in case you're wondering, van Buuren describes his musica as "liberating, euphoric, uplifting, melodic and energetic." Perfect. (DJ Blake Jarrell is also on the playbill tonight). Price: $50 in advance; $275 VIP.

Oct 31 @ 10pm. Rock and erotica ("erocktica") become one at Don Hill's titallating Halloween monster ball. Expect exxxtra special balloons (heh) by J-Party, an erocktica bash at midnight and $500 to the night's best costume. Spooky and sexy. Price: $10 before midnight with flier or printout; $15 thereafter; $20 without flier. Event Phone Number: 212-219-2850

Oct 30 - Nov 1. Only the strong survive during this haunted and ridiculously epic three-day Village-to-Village pub crawl. That'd be the East Village's Pourhouse to the Upper West Side's Pourhouse (recently opened). Miles and miles of $2 Bud Lights (eek), 2-for-1 Pumpkin Ales (better) and 2-for-1 speical Halloween Cocktails that vary at each location. Price: $20 for 1 day; $30 for 3 days

Oct 31 @ 10pm - 4am. Strap on the platform shoes, slither into a disco sequin bodysuit, and channel the old-school Studio 54 vibe with a night of throwback jams at Cache's Halloween blowout. DJ Mister X spins monster '70s and '80s tracks, Disco Diva Amy Douglas gives a mystery live performance, and the night's best costume wins a cash prize. Speaking of costumes, whoever can recreate what that woman in the poster is wearing wins our prize (which isn't cash, it's just a lot, a lot of admiration). Price: $10

Oct 31 @ 9pm - 4am. Room Service and Tens below it join together for one night only into a dual-themed party castle, with the sweetly and luxuriously sexy Heaven upstairs at Room Service (offering shmancy amenities a la a private hotel suite, like curtains, a private mini-bar and a plasma TV), and Hell downstairs at Tens, where the DJ is laying down hip-hop, rock and '80s tracks. An hour of premium vodka open bar is available to all Heaven and Hell-ers, and the DJ spins for angels and demons alike. Costumes are strongly recommended.