Michelle Trachtenberg
Mercy! This Marie Antoinette, who's fabulously halfway through her face-off with the guillotine, has her fortune read during the big bash at 1Oak in New York City.
Paris Hilton & Doug Reinhardt
The heiress and her man give us two tutu-wearing tooth fairies for the price of one at Heidi Klum's bash at Voyeur in West Hollywood.
Nick Lachey & Vanessa Minnillo
Nick's Bel Air pad turned into a haunted mansion for Halloween, where he and Mrs. Stein reportedly showed guests a frightfully good time.
Kellan Lutz & Ashley Greene
The Twilight twosome blows off steam and an aristocratic 'tude at Tao's Halloween bash in Vegas at the Venetian.
Penn Badgley
This is how Gossip guys do birthdays on Halloween—with a gigantic Svedka vodka cake and a handlebar 'stache at 1Oak.
Holly Madison
The Girls Next Door star hosts a costume party at MGM Grand's Studio 54 nightclub, where at least one reveler was dressed as a pregnant Kendra!
AnnaLynne McCord
The 90210 star came as a caped crusader while hosting her sister's 21st birthday party at Tabú Ultra Lounge in Las Vegas.
Mariah Carey & Nick Cannon
Mimi looks angelic and bountiful, making the scene seem downright heavenly at the All Hallows Eve bash at M2 club in NYC's Chelsea neighborhood.
Regis Philbin & Kelly Ripa
The Live stars don a handful of popular costumes, and Jon and Kate Gosselins will be everywhere this season!
Erik Estrada & Ryan Seacrest
The E! star's costume as Ponch from CHiPs is made all the more authentic when its actual star shows up in the studio. The whole thing was made even more ironic when Seacrest's alleged stalker was picked up in the E! lobby at the same time.
Pink
The singer's sad clown costume is so good, we barely recognize the energetic popster behind her Bozo drag at Heidi Klum's bash.
The Today Show
The plaza at 30 Rockefeller Center is tricked out with actual set pieces and costumes from Lucasfilm!
Ed Westwick
The Gossip Girl It guy doesn't need a costume to attract the ladies, so he barely makes an effort, posing here with party hosts Lauren Auslander and Angela Nile at the Soho Grand Halloween Party Sponsored by Dos Equis in NYC.
Mickey Rourke
The Wrestler star pays homage to Heath Ledger and dresses as the Joker for a party at Club Voyeur in Hollywood.
Rachael Ray & Rosie O'Donnell
This Wizard of Oz-themed photo might be the scariest of the bunch. Glinda, the good witch? Really?!
Chelsea Handler & Chuy Bravo
E!'s own late-night diva was Queen of the Carnival at the West Hollywood parade, accompanied by her TV sidekick.
Audrina Patridge
Halloween is all about coming as you really are, and it seems this Hills star is really one hot bird.
Holly Madison
The Dancing with the Stars contestant shows a different athletic side, stripping off her shorts to become becah babe Pamela Anderson à la Baywatch.
Charlie & Jerry O'Connell
When was the last time you saw a shark and killer whale this adorable? The brothers donned their swimsuits for a Camp Ronald McDonald Halloween Carnival.
John Legend & Chrissy Teigen
Playing cowboys and Indians is a game that's obviously working for this couple, who've buried the hatchet with no reservations as they celebrate in West Hollywood.
The View Girls
The first ladies of The View took it purely presidential for their Halloween talk show special.
Christian Siriano & Heidi Klum
Flamboyant Project Runway winner Ferosha Coutura meets up with multi-armed deity Kali at the supermodel's annual Halloween bash in NYC.
Kim Kardashian & Reggie Bush
Looking gangsta gorgeous, the football star and his foxy flapper moll rule the carpet at the Pur Jeans bash at STK restaurant in Los Angeles.