New Year's Eve 2013 | Mike Posner and Bad Boy Bill at the Hilton

The Chicago Hilton hotel hosted the latest iteration of its annual New Year's Eve party, where rapper Mike Posner performed for a crowd both well-dressed and bunnily-clad (thanks to Playboy, who had sent a few emissaries the event). Posner, sporting the familiar plain sweatshirt, rang in the new year with the support of Chicago house DJ Bad Boy Bill. Check the slideshow for photos from throughout the night.