Mommy-to-be Ashlee Simpson-Wentz celebrated her 24th b-day (her last one sans child) with a "white-trash theme" soiree. "Ashlee wore Daisy Dukes and platform flip-flops with a bathing suit and a fake tattoo around her belly," a guest tells People. Guests like hubby Pete Wentz, father Joe Simpson (dressed in "a cut-off muscle T-shirt and a mullet wig"), and sister Jessica Simpson (in "a crazy leopard-print dress that showed off a lot of cleavage") noshed on corn dogs, macaroni and cheese, chicken fingers and French fries. "Ashlee loves themed parties and costumes," a pal says. It seems so! Last year, she had an '80s prom night party, and her wedding was Alice in Wonderland-themed.

But the preggers guest of honor left the party early, missing guests like Christina Aguilera, Nicole Richie, and Joel Madden, who showed up after attending Gwen Stefani's 39th b-day bash beforehand.

We can see why they hit up both -- Gwen's dance party sounds pretty fab, too! Attended by 100 guests, including Xtina, Nicole, Joel, Ashton Kutcher, Demi Moore, Ellen DeGeneres, Portia De Rossi, Gwen's No Doubt band mates, and of course, the Harajuku Girls, the dance party was hosted by hubby Gavin Rossdale at their house. "The deejay played great music from the '80s and all [Gwen's] favorites -- reggae, songs by The Specials, Fishbone, The Police," a partygoer spills. "She danced all night and went from person to person just being the birthday girl." Fun!