Questlove spun at the bash.

For reference, this is Heidi at a UNICEF event in Boston the night before, with "Project Runway" co-star Tim Gunn.

Back on Friday night at Heidi's, Ashanti took over a table like royalty.

Coco and Ice-T made the scene.

The hardcore boxing trainer who trains Wall St. wussy guys (his words, not mine) Eric Kelly. You may remember him from a viral video that launched a flood of incoming reality TV offers.

The scene at Heidi's.  She got Svedka vodka and Moto X to sponsor her bash, now in its 15th year.

NYC photographer of the scene Jamie McCarthy channeled "The Walking Dead".

Russell Simmons dressed as the seminal hip hop group he helped start, Run-DMC.

Run-DMC was popular, as Brian Grazer (left) chose the same rig at the Treats Magazine party in L.A. David Spade is on the right.

Twinkie the Kid at the Treats! Party, which is a magazine all year, but has the best name for Halloween eve.

Gerard Butler takes on another period piece.

So great to see the old crew from Hyde 2005 all together again: Brandon Davis, Paris Hilton, and Spade, all at Treats.

Two brits behind the decks. Zen Freeman and Boy George.

Robin Thicke emerged from the VIP room at Treats, where Leonardo DiCaprio wandered in a gorilla mask.

Bill Maher on his way in to the bash.

Derek Hough continued his WTF-no-costume look this Halloween season.

We've all known that Ryan Seacrest is an entreprenurial genius for building his empire from Star 98.7 drive time to now. He showed off as Einstein. His buddy on the left, photographer Steve Shaw.

Up in West Hollywood., that massive throng on Sunset was the crowd trying to get in to Adam Lambert’s 2^nd annual Halloween party.  Michelle Pesce played the Halloween parade on Santa Monica Blvd., then climbed the hill to play Bootsy’s famed back room.  This host is on his way to Klum status with this costume.

Hoping that Kelly Osbourne's fur is fake. 

Deadly couple Shenae Grimes and Josh Beech.

“Rich Kid of Beverly Hills” Dorothy Wang at Bootsys, right on the border of her town.

Aubrey O'Day subliminally reminds everyone that she was on "Celebrity Apprentice" on the peacock network.

In a year light on iconic pop culture images to borrow for Halloween, publicist Rembrandt Flores nailed one of them as Pharrell Williams, and the Arby's hat. Michelle Rodriguez posed with the guy shuffling the deck at Treats' bash, which got Absolut Elyx in as a sponsor.

Lady Gaga must have watched the Charlie Brown "Great Pumpkin" special on the plane over to Paris.

In London, Kate Moss dressed as her colleague, wild child model Cara Delevigne. They went to London’s hot party, thrown by TV host Jonathan Ross.

That's Rita Ora on the right.

A few nights earlier, the rope parted at famed club Annabel’s in London. Nick Grimshaw, Jaime Winstone, and Harry Styles came to celebrate the Ridley Scott produced doc "A String of Naked Lightbulbs" about the perennial hotspot on Tuesday night.

Zoe Kravitz and Joe Jonas at Heidi's bash.

Earlier in the night, Kravitz DJ'd the float for TheWrap's Halloween party partner Freixenet in the NYC Halloween parade.

There were costumes at the screening of Radius-TWC’s “Horns” on Thursday night, but no horns on lead Daniel Radcliffe. With Radcliffe at the Wood & Vine after party: Producer Cathy Schulman, Mitchell Kummen and Sabrina Carpeenter. Vaporizer Pax by Ploom presented the night.

There were sort-of costumes at amfAR's mega bash on Wednesday night.

Not Justin Timberlake’s first time riding shotgun on a semi-bedazzled and exposed nipple in public. This time, Rihanna took the honors at the amfAR Inspiration Gala that raised over $3 million at Milk Studios. Belvedere vodka kept the cash flowing.

Another look at Rihanna's style. 

Meanwhile in more traditional party gear, British Ambassador Sir Peter Westmacott came from Washington, D.C. to Thursday night’s Britannia Awards.  He joined one of his own, Dame Judi Dench, at the Beverly Hilton proving the concept behind the “GREAT Britain” campaign.

Brit director Mike Leigh (left) was honored at the Britannia Awards for his work on this year’s “Mr. Turner”. 

Kristen Johnston, David Alan Basche, Donald Faison, Kelly Stables, Wayne Knight and recurring guest star Leah Remini launched TV Land’s “The Exes” new season with an Oktoberfest party at L.A. german restaurant Wirtshaus

William H. Macy and Don Cheadle led “Showtime’s” cross-series Habitat for Humanity volunteer day in L.A. on October 25.

Laurie Metcalf and Michael Lomardo grabbed some (reserved) couch space at the second season premiere of “Getting On” at the Avalon on Tuesday.

Before heading off to the Art of Elysium gala, Zach Braff and Sarah Hyland filled two of the seats at the spaceship-ish Samsung Galaxy Note Pad in Beverly Hills, a four day mega-mansion hosting parties for the launch of the Galaxy Note 4.

“The Mirage" is a documentary about NYC real estate mogul Peter Kalikow's (center) lifelong pursuit to build his dream car from scratch. At the Philadelphia Film Festival premiere, director Kyle Roper and Producer Nicholas Kalikow. 

Adam Levine moved his annual party to the valley (gasp), but pulled it off.  Behati Prinsloo came ready to get "physical."

Levine converted the famed Sportsmen's Lodge in to the "Friday the 13th" themed Camp Crystal Lake.

"Maroon 5" performed as Motley Crue and appropriately brought in an alcohol partner, Dos Equis, to fuel the bash.