Mayor Bloomberg, Anna Wintour, Tommy Hilfiger, Donna Karan, designer Marcus Wainwright, Mary-Kate Olsen Marc Jacobs 2010 Fashion's Night Out Kick-Off press conference City Hall

Left to right, Mayor Bloomberg, Anna Wintour, Tommy Hilfiger, Donna Karan, Rag & Bone's Marcus Wainwright, Mary-Kate Olsen, and Marc Jacobs at the 2010 Fashion's Night Out press conference at City Hall in NYC. Photo: Larry Busacca, Getty Images / Conde Nast

New York City Mayor Michael Bloomberg, flanked by over a dozen design luminaries and Vogue editor-in-chief Anna Wintour, announced the details of Fashion's Night Out 2010 this afternoon.

Now in its second year, Fashion's Night Out will be held Sept. 10 throughout New York City, with nearly 1,000 retailers participating in the after-hours shopping spree.

Stores will stay open until 11 p.m., hosting all sorts of special events, from designer appearances to live performances. Barneys, for instance, will boom with a karaoke contest judged by Mary-Kate and Ashley Olsen, Simon Doonan, and Proenza Schouler's Jack McCollough and Lazaro Hernandez. (Start practicing with your hairbrush-microphone now.)

Many stores will produce exclusive merchandise. Bergdorf Goodman plans to introduce New York-themed items such as TOMS shoes decorated with a Manhattan skyline print.

Speaking at City Hall, Mayor Bloomberg said the event originated when Wintour and designer Diane von Furstenberg approached -- or rather, steamrolled -- him with the idea. "They came to me and said, 'You're going to do this,'" he chuckled.

Steve Sadove, the CEO of Saks Fifth Avenue, explained, "We've been working on this mantra of 'Don't let a good recession go to waste,'" as his company works with New York City agencies to support innovation in the design community.

Whether the participating stores actually get a significant financial boost is debatable, but Sadove observed that the previous Fashion's Night Out marked an uptick in the retail industry overall. "We started to see a turn in the industry, sales started to stabilize," he claimed.

Marc Jacobs, wearing a black kilt/Bermuda short hybrid, grinned as he described his experience during last year's event, when he tried to walk between his office and his Mercer Street boutique.

"It took me about two hours to get two blocks," he recalled of being mobbed by shoppers. "It felt like a block party... it felt like what shopping is all about, the social ritual."

"Being the Luddite that I am," Jacobs explained, diamond earrings a-twinkle, "I was really happy to see people not in front of a computer screen, adding to their cart... but getting out, interacting with each other, being out on the streets of the city."

Other attending designers included Donna Karan, Tommy Hilfiger, Carolina Herrera, Tory Burch, Zac Posen, Prabal Gurung, and the two very different Wangs, Alexander and Vera.

To whet the public's appetite, Fashion's Night Out will be preceded with the city's largest public fashion show Sept. 7, curated by Vogue staff.

In a press statement, Wintour said, "We've focused the show on the trends we thought were most important, so that no matter what their style or budget, shoppers will have a source of inspiration."

(While Wintour didn't speak at the press conference, she wore a look straight out of "The September Issue," with a knee-length pleated skirt and sparkling choker necklaces.)

The massive runway rolls out at Fashion Week's new location, Lincoln Center, and tickets go on sale Aug. 19 at the Lincoln Center box office. Prices start at $25, with proceeds going to the NYC AIDS fund.

Backed by NYC & Company, more than 40 Manhattan hotels are offering special Fashion's Night Out packages.

The celebration will pollinate other U.S. cities, from Los Angeles to Chicago. Major retailers with stores across the country, such as Neiman Marcus and Saks Fifth Avenue, will host tie-in parties at their various branches.

Fashion's Night Out will spread overseas, too, from Paris to Tokyo. More event details will be announced later this month.

If you can't get to the events in person, CBS will air a behind-the-scenes special showing Fashion's Night Out's global reach Sept. 14 at 10 p.m.

Read on for the scoop on CBS's Fashion's Night Out contest!