From a Congressman refusing to pay his cab fare to a certain staffer misusing a listserv, 2010 was a good year for gossip. We’ve sifted through dozens of columns and found the most salacious, titillating and hilarious gossip of the year. And we’ve now reached the top (or bottom, depending on whom you ask).

In our No. 1 spot is now-retired Rep. Patrick Kennedy (D-R.I.), who spoke one April evening at a charity fundraiser about his struggle with alcohol and drug abuse … only to be spotted a few hours later taking vodka shots at a beloved Capitol Hill watering hole.

“Kennedy’s Vodka-Fueled Bar Trip” From April 27:

Rep. Patrick Kennedy was spotted doing vodka shots last week at a Capitol Hill bar just hours after he spoke about his history of substance abuse at a charity event.

An HOH tipster and a pal were sitting at the bar at the Capitol Lounge around 11 p.m. on Tuesday when the Rhode Island Democrat walked in and took a seat between the pair. The tipster’s friend asked the Congressman what he was drinking, and when Kennedy replied vodka, the group ordered vodka shots, the tipster tells us.

After slamming down the first round, another was ordered, then a third. Our tipster and his friend stopped doing shots, but Kennedy drank three more until the bartender cut him off, at least from obtaining any more shots, our tipster says.

Our tipster adds Kennedy was in a lively mood, joking with others at the bar and even boasting about President Barack Obama, calling him “the best president ever.”

When our tipster countered: “Wait a second. What about your uncle?” — referring, of course, to President John F. Kennedy — the younger Kennedy jovially responded, “Oh yeah! Good one,” and slapped our tipster’s back, he says.

No word on when Kennedy left the lounge, as our tipster headed out before the Congressman.

Earlier in the night, Kennedy received an award for his work on mental health issues at the annual fundraising dinner for N Street Village, a local charity that helps low-income women battle homelessness and drug addiction.

Kennedy — who was introduced at the soiree by his one-time substance abuse sponsor, former Rep. Jim Ramstad (R-Minn.) — touched on his personal history in his acceptance speech. The Congressman recalled the late night in 2006 when he crashed his car into a Capitol Hill barricade and subsequently headed to rehab for a prescription drug addiction.

HOH’s multiple calls and e-mails to Kennedy’s office seeking comment were not returned by press time.