The passing of another year in age-obsessed Hollywood doesn't seem like much cause for celebration, but that didn't stop a couple of big names from marking their big days.

On Wednesday, Lindsay Lohan rang in her 22nd birthday by regressing to her teens with a prom-themed shindig at Teddy's in Los Angeles.

She was accompanied to the high school-inspired soiree by constant companion Samantha Ronson, with a spy relaying to the New York Post that the lately self-restrained starlet "came as the prom queen in a pink dress and Sam was her king in a black top hat and vest."

Several dozen of Lindsay's pals -- along with mom-ager Dina and little brother Michael -- turned out for the balloon-festooned bash, and People says she greeted each guest "energetically with smiles, hugs and kisses."

Ronson, adds the mag, shadowed her throughout the evening, "often keeping her hand on the small of Lohan's back."

When midnight struck, Lindsay was presented with a cake decorated with a picture of her idol, Marilyn Monroe, in that classic halter-dress-meets-gust-of-subway-wind pose from "The Seven Year Itch."

She was then serenaded with a round of "Happy Birthday" but responded to shouts of "speech, speech, speech!" by good-naturedly ribbing her friends, "Shut the [bleep] up."

In a hopeful sign, Lohan reportedly downed only Red Bull during the party, which gave her plenty of energy to groove to Journey's "Don't Stop Believin'" when Ronson went into DJ mode.

At one point, Linds was spotted enjoying a quick lip-lock with Sam in the DJ booth, says People.

The night ended as it began, with Lohan and Ronson glued to each other's side.

"I've never seen her happier," a spy tells Us.

The next day, LiLo gave Ryan Seacrest a call to chat about her hopes for the upcoming year, which, fingers crossed, will have less drama than the previous one, what with her DUIs, trips to rehab and spiraling career, not to mention the recent revelation that she may have a half-sister.

"I just want to live a happy, healthy year," said Lohan, "and continue on the path I've been on and be with the person I care about and my family."

By the by, Lindsay and the person she cares about were snapped enjoying the rides at Disneyland on Thursday and making a video run together on Sunday following an al fresco, paparazzi-accompanied lunch.

Pam has her cake and tongues it, too.

Meanwhile, Pamela Anderson whooped it up as parts of her turned 41, an occasion she rang in with a soiree at Las Vegas hot spot LAX on Saturday night.

Like Lindsay, she opted to don pink for her special day, and while lightbulb love Tommy Lee was a no-show at the bash, she wasn't lacking for questionable company.

The worse-for-wear-looking bombshell was snapped wrapping her arms around and looking generally cozy with cringe-inducing illusionist Criss Angel.

Still, Pam's handsiness with the prestidigitator was preferable to the saliva-soaked moves she used on her flower-topped cake, a lovely confection that deserved better than being tongued by the birthday girl.

Next: J.Lo and Jim Carrey: Bathing Beauties