Have plans for New Year’s Eve yet? Cosmopolitan Las Vegas may have your plans wrapped up, that is, if you can get an invitation. The newest resort, which plans to open in December, is celebrating its world premiere opening by ringing in the New Year with a multi-day celebration featuring solo and mash-up New Year’s Eve headline performances by Grammy award-winning artists Coldplay and Jay-Z. The collaboration is officially dubbed “Viva La Hov featuring Coldplay and Jay-Z.”

If it’s cars you love, you need to be in Vegas this week when Barrett-Jackson Auction Co. and MGM Resorts International present the Third Annual Barrett-Jackson Las Vegas Auction. Think of it as five days of cars, chrome and neon. The “REVVED” days will take place Wednesday, Sept. 22, through Sunday, Sept. 26, with featured events at all MGM Resorts International properties.

Wolfgang Puck is running late, and it’s a good thing. I am too. But once “Pretty Vegas” from INXS fades from the speakers and the chefs on stage have stopped their last-minute preparations, Puck walks out on stage for the members of the Grazie loyalty program at the Palazzo and Venetian. It’s a live cooking demonstration by the chef himself, where he spent more than an hour cooking three dishes and charming the audience.

Ginnifer Goodwin, star of HBO’s “Big Love” and the blockbuster hit “He’s Just Not That Into You,” treated younger sister Melissa to a bachelorette weekend at the Palazzo Sept. 17-19.

With her upcoming nuptials to Russell Brand quickly approaching, Katy Perry celebrated one of her last nights as a single woman with a bachelorette party at Hard Rock Hotel. The large group, which included good friend Rihanna, checked into Casino Tower and started festivities in a private cabana at HRH Beach Club.

Sexy actress Amber Lancaster from “The Hard Times of RJ Berger” celebrated her birthday last night at Tabú Ultra Lounge inside MGM Grand, making her first public appearance with her hunky actor beau Zack Conroy from “The Bold and the Beautiful.”

Singer Mike Posner might be one of the hardest working performers in show biz. Following his concert at the House of Blues at Mandalay Bay, Posner headed to Blush Boutique Nightclub at Wynn Las Vegas to perform at the venue’s three-year anniversary party. Posner stood atop the bar and sang three songs, including his hit “Cooler Than Me.”

It was a night of romance at Tabú Ultra Lounge at the MGM Grand last night when Shayne Lamas of “The Bachelor” fame and Nik Richie from The Dirty.com celebrated their bachelorette and bachelor parties. The couple, who got hitched in Las Vegas on April 18 amid a whirlwind romance, celebrated their unconventional post-nuptial bachelor and bachelorette parties with style as they partied the night away to the beats of DJ Forbes.

Simon Rex, aka Dirt Nasty, and Beardo hosted at Tao’s Worship Thursday at the Venetian last night. The duo dined at the Asian bistro, gearing up for the night with cocktails such as the Demon Slayer and Tsing Tao along with favorites including the sea bass and lobster wontons.