Stars descend on Washington for White House dinner

• Among the celebs expected%3A Steven Spielberg%2C Michael Douglas%2C Scarlett Johansson
• The dinner is held in a cavernous Hilton Hotel ballroom in D.C.
• President Obama has gotten good reviews so far for his dinner laughs

It's not the Oscars but it's the best Washington can serve up in the glittery category: It's time once again for the White House Correspondents Association's annual dinner gala on Saturday night.

Among the boldfaced names expected: Steven Spielberg, Barbra Streisand, Michael Douglas, Scarlett Johansson, Reese Witherspoon, Jon Bon Jovi, Tracy Morgan and a host of others.

Held in a cavernous Hilton Hotel ballroom, the dinner is a sure sign of spring, a night when the White House press corps and White House denizens come together to drink, eat, tell jokes and hold off plotting against each other for a few hours.

This used to be a fairly staid, even professional affair, useful for allowing predators and prey to relax and get to know each other in an atmosphere of bonhomie achieved by gallons of free-flowing liquor.

Then, back in the 1980s, someone in the press corps got the bright idea of inviting celebrities — real celebs — to be their guests, and soon the starry look of the whole affair had jumped a hundredfold, complete with red carpet and paparazzi.

Now news organizations spend months competing with each other over which Hollywood diva they can persuade to sit at their tables.

Meanwhile, grandees of the White House press corps are delegated to find just the right jokester host who can actually be funny, or at least won't embarrass them. This year, that man is late-night host Conan O'Brien, making his second appearance at the dinner (he first headlined in 1995).

The president is expected to perform, too, by delivering a funny speech. President Obama has gotten good reviews so far for his dinner laughs, including in 2011 when he was one of the few people in a room of hundreds of journalists who knew the operation to capture Osama bin Laden was underway that night.

This year demonstrates again how much the power structure of the mainstream media is shifting. Yes, old media attract big names (Time has Spielberg, Bloomberg has Streisand) but newer names attract big names, too (Daily Beast has Witherspoon and Harvey Weinstein, and Huffington Post has Shaquille O'Neal and Johansson).

USA TODAY's guests include Josh Gad (Book of Mormon, 1600 Penn), Megan Hilty (Smash), and Kate Walsh (Private Practice).