Whoa, Baby! Mary-Kate and Ashley Turn 21

Thu., Jun. 14, 2007 10:41 AM PDT by Sarah Hall

So, Mary-Kate and Ashley Olsen walk into a bar, sit down, and order drinks. The bartender says, "You got it, dude."

The twin sisters celebrated their 21st birthday with a laid-back dinner party at Los Angeles' Chateau Marmont Wednesday, eschewing the wild festivities with which many of their peers might commemorate the same milestone. (Ahem, Lindsay Lohan.)

Their 19-year-old sister, Lizzie, and 23-year-old brother, Trent, were among the guests who turned out to wish them many happy returns.

Aside from attending the intimate gathering, the former Full House stars spent their birthday "doing absolutely nothing," according to a message to their fans posted on their official Website Wednesday.

"Thanks for all of your birthday wishes," the twosome wrote. "The past year has been incredibly rewarding. We have tons to be thankful for. Most of all—YOU—our fans. Your support is amazing and inspiring."

The hard-working minimoguls sounded ready for a break from the daily responsibilities of running their multimedia empire, Dualstar Entertainment Group, over which they assumed control in January 2005.

"Today, for the first time in a looooong time, we're taking a day off—doing absolutely nothing and looking forward to every second of it!" they wrote.

The duo's downtime won't last long.

Mary-Kate recently landed her first solo television role as a recurring character on Showtime's Weeds, playing Tara, a good Christian girl who's the love interest of Silas (Hunter Parrish), the son of Mary-Louise Parker's character, Nancy Botwin.

She'll appear in 10 of 15 episodes in the third season, which premieres Aug. 13.

It's the first major acting role for either twin since their 2004 box office flop, New York Minute. Though Mary-Kate landed a part in last year's Edie Sedgwick biopic, Factory Girl, her scenes wound up on the cutting-room floor, aside from a brief background appearance.

Though Ashley currently has no acting projects on the horizon, she's remaining plenty busy overseeing the twins' various business ventures, including their new fashion line, the Row, which launched earlier this year.