We all knew he was a smoker. But there’s another reason President Barack Obama’s mouth might need a good washing out.

[IMGCAP(1)]From the department of why-didn’t-we-know-this-sooner: Obama himself narrates the audio version of his bestselling memoir, “Dreams From My Father,” including a passage in which he describes conversations with an old classmate named Ray, who is, like Obama, bi-racial. Ray, it seems, has a fondness for profanity, including prolific use of the f-bomb. And the n-word.

And so you have Obama (quoting Ray) using phrases like, “Ignorant motherf****ers,” “You ain’t my b****, n***a.”

Yes, folks, that’s our president uttering words we’re more used to hearing from foul-tongued comic Dave Chappelle.

L.A. comedian April Winchell has helpfully assembled audio files of all the best quotes on her Web site, aprilwinchell.com.

Go ahead, just try to resist playing them over and over.

Senator to the Stars. Sen. Barbara Boxer is known as a celebrity-friendly Member of Congress, with a campaign donor list that includes A-listers such as Barbra Streisand and Steven Spielberg.

And on Wednesday — which wound up being a huge day for famous folk hitting Capitol Hill — the California Democrat’s dance card was filled with visits from celebrity lobbyists.

Boxer or her staff met with actor Ted Danson (who also testified at the House Natural Resources Committee hearing on offshore drilling), actress Maria Bello (who is promoting awareness of violence against women in Darfur) and even “Hercules” actor Kevin Sorbo, who is seeking federal funding for his after-school program, “A World Fit for Kids!”

Danson called Boxer one of his favorite Members, praising her acting ability (the two appeared together on an episode of the TV show “Curb Your Enthusiasm”) and calling her an “old friend.”

In other star-watching developments, Sorbo chatted with HOH about his “Kids!” program, which offers exercise, mentoring and tutoring for at-risk students in Los Angeles. “It’s an hour of activity, and then boom, it’s hit the books,” Sorbo explained.

Aside from Boxer, Sorbo visited the offices of California Sen. Dianne Feinstein (D) and Golden State Reps. Xavier Becerra (D) and Lucille Roybal-Allard (D).

And Boxer wasn’t the only Member mixing with celebrities.

Singer Carole King joined Reps. Carolyn Maloney (D-N.Y.) and Raúl Grijalva (D-Ariz.) at a press conference introducing legislation that seeks to protect land in the Northern Rockies.

Actor (and possibly future New Mexico gubernatorial candidate) Val Kilmer also milled around Capitol Hill, at one point dropping into Rep. Ben Ray Luján’s office to chat with the New Mexico Democrat and his staff. The “Top Gun” star is scheduled to meet with New Mexico Sen. Jeff Bingaman (D) today, HOH hears.

Double Date With the Clintons. Actor Ted Danson wasn’t just in Washington to fight offshore drilling or to chat with Sen. Barbara Boxer (see previous item); he was here for a reunion. Danson and his wife, actress Mary Steenburgen, had a Tuesday night dinner with another famous power couple — the Clintons.

Danson and Steenburgen are longtime friends of the former first couple, but Danson told HOH they hadn’t hung out since the presidential campaign, when both actors campaigned for Hillary Rodham Clinton and then alongside her on behalf of President Barack Obama.

“It was lovely to see them,” Danson told HOH of the get-together.

By hobnobbing around Washington, Danson ran the risk of running into former “Cheers” cast mate Kelsey Grammer, who was in town for the reopening of Ford’s Theatre that evening. Danson says that despite their very different political stripes — Grammer is one of the most vocal Hollywood Republicans and Danson’s obviously a big Dem — they remain good friends, and the former “Frasier” star has been supportive of Danson’s clean-oceans work. “We were laughing and working hard for 10 years,” he said of their “Cheers” days. “Even if we do disagree on many things.”

Bat Upstages Mac. Sen. John McCain was nominally the man of the hour at a Tuesday night event sponsored by Tracy’s Kids, a nonprofit that helps children with cancer and their families. The Arizona Republican, himself a survivor of melanoma, received the charity’s Courage Award — but Sen. Patrick Leahy (D-Vt.) stole some of McCain’s thunder.

Leahy’s cameo role in the Batman movie “The Dark Knight” was Topic A among lawmakers attending the fete, since the film was being screened, along with five other Oscar-nominated films.

Sen. Benjamin Cardin (D-Md.) was there to catch his friend’s big-screen performance. “I have to, because Sen. Leahy is in it,” he said when asked which screening he planned to attend that night.

And Leahy himself played it faux-modest about his brush with stardom. “Wonderful cameo by a U.S. Senator,” he said, grinning, explaining why he thought “The Dark Knight” was the best movie being shown that evening.

In Defense of Sin [City]. What happens in Vegas? These days, not much — and Rep. Shelley Berkley blames her Congressional colleagues and President Barack Obama for that.

The Nevada Democrat released a statement on Wednesday arguing that politicians are unfairly targeting Las Vegas when they blast the excesses of corporations who have received bailout money. Obama, for example, recently said that corporations receiving bailout funds “can’t go take a trip to Las Vegas … on the taxpayer’s dime.”

While curbing excess is a worthy goal, Berkley wants to “call a cease-fire” on the whole pick-on-Vegas schtick, saying that specifically targeting the city only hurts her constituents. “There is no question that as a result of the criticism leveled against business travel to Las Vegas by the president and others, the community I represent has lost millions of dollars in revenue,” Berkley said.

Trade shows, conventions and corporate gatherings in Vegas actually help the country’s overall economic health, she argued, as such events “fill airline seats, hotel rooms and restaurants.”

Spokesman David Cherry said the Vegas-bashing is giving the city a stigma. “This thing is snowballing to where anybody who is coming to Las Vegas feels bad they are taking that trip,” he said.

So go ahead and hit the poker table — just be careful not to lose too much cash.

Change You Can Be-Leaf In. That wasn’t just hope in the air during inauguration week.

Just ask the Capitol Police. There were pot busts a-plenty the day after President Barack Obama’s swearing-in ceremony.

Officers on duty at the Capitol Visitor Center the morning of Jan. 21 were doing a routine search of an unnamed visitor when they noticed a white pill container “filled with a green leafy substance,” according to a police report. A test revealed the said foliage to be marijuana, according to the report.

About an hour later, the officers at the CVC were conducting another search and spotted “a quarter size hand rolled cigarette” on another visitor. That cigarette was tested and found to be marijuana. Both received misdemeanor marijuana-possession charges.

Insert joke about college kids here.

Charlotte Wester contributed to this report.

Submit your hot tips, juicy gossip or comments here.