What's it really like inside a Hollywood party?

Ordinary stargazers dream of answering that question and living the VIP life, particularly on Oscar Night when Los Angeles is awash with star-studded after parties.

But not every star gets the VIP party treatment, however. Just ask actress Sean Young, who was denied entry to the Oscar's official party.

While Brad Pitt, Angelina Jolie and other A-listers were welcomed like royalty at this year's Governor's Ball on Feb. 26, Young's name failed to make the guest list.

Allegedly, the "Blade Runner" actress attempted to crash the event without a ticket. That move lead to an altercation with a security guard and Young being "carted off," as she later told reporters, to a Hollywood police station.

Young isn't the only star to make headlines over the last year for some questionable party conduct.

In 2010, Sean Penn was thrown out of the Governor's Ball for allegedly punching "Hurt Locker" producer Greg Shapiro. The event was reported by E!'s Giuliana Ransic. Penn's reps, however, claim the incident did not happen.

Earlier this month, P. Diddy hosted a tony bash in Connecticut to celebrate the 20th anniversary of the Foxwoods Resort Casino. The event ended with a 2 a.m. brawl in the MGM Grand Casino's lobby, with charges laid against hip-hop artist Jim Jones for resisting arrest, breaching the peace and assaulting a police officer.

The incident did little to dampen Jones's spirits. He went onto Twitter a few hours after the brawl to give his followers the inside scoop: "40k in bonds 1 night had a ball let see (if) I can get th(a)t 40 back on th(e) crap table."

Bad behaviour like this will always sell tabloids and amuse the masses. But throwing a few punches isn't all that it takes to get a celebrity booted off a VIP party list.

Cameron Diaz, for example, was "blackballed" from Madonna's swanky Oscar bash this year according to the U.K. tabloid "The Daily Mirror."

Madonna has hosted that Oscar event for the last two years with actress Demi Moore.

Diaz earned this slap, allegedly, for flirting with Ashton Kutcher, Moore's ex, at a Golden Globes party last month.

Moore and Madonna weren't the only ones scrutinizing their guest lists this year.

Elton John reportedly took his time to consider who would sit next to him at his annual AIDS Foundation Oscar bash. On Sunday, John finally awarded that honour to Katy Perry -- a star he admired and wished to know better.

John also personally invited the newly-single Heidi Klum and Kim Kardashian. According to "The Daily Mirror," John thought it would be a good way to show his support and, possibly, land them new men.

Whatever their reasons, stars are people. If you're liked, you're in. If not, you're out.