IT'S THE END of an era: After 20 years pouring pints of Guinness and hosting rock and folk bands (and suffering through innumerable versions of "the Unicorn Song"), Flanagan's Irish Pub (7637 Old Georgetown Rd., Bethesda; 301-986-1007), which bills itself as the oldest bar in Bethesda, closes its doors forever on Oct. 9.

The small, well-worn, cellar-level tavern wasn't done in by the smoking ban or a lack of patrons. Like its neighbors at the corner of Old Georgetown Road and Woodmont Avenue, Flanagan's is being razed and replaced by condos.

When a bar closes after two decades, nostalgia settles in all too easily -- laughing about the long, narrow flight of stairs that lies between the front door and that first view of the bar instead of cursing its existence. Friends who'd wrinkled their noses as the trademark odor of stale beer and cigarettes -- which lingered long after smoking was banned -- make jokes about missing that scent. I've even heard one buddy of mine muse about the "Grout Wall of Flanagan's," a long-running "tradition" that consists of patrons writing bad puns like "the grout escape" and "that's just grout" in the white spaces between the ceramic tiles over the urinals in the men's room.

Reminiscing about these little touches makes it easier to forget that the building itself was a dim, windowless basement that even co-owner Steve Nugent jokingly compared to "a prison." The atmosphere came not from the Irish tricolor hanging behind the stage, the oil painting of John F. Kennedy, the televised soccer or even the Guinness. What made Flanagan's so special were the people: the friendly bartenders with authentic brogues, the relaxed regulars who never fit easily into one demographic category.

As in a true Irish pub, it was pretty much a given that you'll find two or three generations drinking side by side -- maybe throwing darts, probably watching sports on TV, more likely conversing loudly with the bartender and the people sitting next to them, whether they were on a first-name basis 15 minutes ago or not.

"There's something about that place," says Joe Crosby, whose Celtic rock band Scythian is playing at Flanagan's tonight and next Friday. "When you think of an Irish pub, it's a friendly, family affair. Most Irish bars at this point have gone corporate and they'll probably never get that back. Flanagan's has preserved that feeling."

"We know 70 to 75 percent of the people that come in to Flanagan's," says co-owner Patrick "Paddy" McDonagh. "And if they're not a regular, they'll be one in a few weeks.

"We were so used to the regulars," the Belfast native says, "that when they came in, we could tell by their shins who they were. By the time they got halfway down the stairs we could get their drinks ready for them. Most places need a face to put to a drink. All we needed was a pair of shoes. That's what I'll miss the most. When you can put a pair of Nikes to a drink, you know your customers well."

It's that kind of relationship and loyalty that the owners are banking on as they prepare to vacate the space.

"We always knew [the closing] was possible," says Nugent, another native of Belfast, who arrived at Flanagan's 16 years ago and worked his way up to manager and, four years ago, an owner. When the guys found out last year that they'd have to leave, Nugent says, "we wanted to stay in Bethesda. We were looking at other places outside of Bethesda, but all our staff had been with us 10 years or longer, and the customers are here."

The perfect fit, it turned out, was about three blocks away at a restaurant previously known as the Red Heifer and Cottonwood Cafe. Nugent, McDonagh and partner Mac McTigue had their new space, dubbed Flanagan's Harp and Fiddle (4844 Cordell Ave., Bethesda; 301-951-0115), open about five weeks after signing the lease, giving them a few weeks of overlap "so we could steer people over here," McDonagh laughs.

Although they have knocked down a few walls and added Celtic designs to others, the Harp and Fiddle doesn't seem that much different than the restaurants previously located there. Compared with Flanagan's, though, it's like night and day. Large windows look onto the street, and a patio with space for about 40 lies just outside. Inside, the focal point is a huge bar, surrounded by high tables and stools, but smaller dining areas in the back make it clear there will be an emphasis on food, at least early in the evenings. The rear dining room shows the balance the owners have in mind: Handsomely decorated with wood paneling and stone accents, it has a projection screen that can be raised discreetly to the ceiling. After the original Flanagan's closes, Nugent plans to move the dartboards over but hide them inside tasteful cabinets until after dinner, when the china disappears and the darts begin to fly. A raised platform with dining tables will eventually be converted into a stage for live music.

Instead of the usual Guinness posters, McDonagh says, artistic family members from Ireland are coming over to hang their own watercolors and landscapes. Some old mementos will find their way over from Flanagan's, McDonagh says, "the portrait of President Kennedy, and the Flanagan's mirrors with the logos, so that people know where they are."

Actually, he says, "we're going to take the bar from Flanagan's and put it outside and put the mirrors behind it, so you can sit at Flanagan's bar on the patio."

While Nugent and McDonagh wax nostalgic about the old space, they keep stressing the advantages of the Harp and Fiddle. The previous occupants left a smoker, which Nugent has already started using for venison and duck, moving well beyond the Flanagan's staples of wings and Shepherd's Pie. They also hope to lure back some smoking customers with the patio. Business at Flanagan's declined dramatically after the smoking ban, McDonagh says, as customers seemed reluctant to leave their beer at the bar and climb a flight of stairs to have a cigarette.

Events marking the last 10 days at Flanagan's are designed to reward regulars and neighbors: happy hours with free food and cheap drinks for employees of the Naval Medical Center (Oct. 4) and the National Institutes of Health (Oct. 5), and a "couples party" with Scottish band North Sea Gas on Oct. 6. "Over the years, so many people have met there, so we thought it would be nice to have one last date night," Nugent explains. The couple with the best "how we met" tale gets a free dinner at the Harp and Fiddle.

Scythian hosts the "Last Friday" party on the Oct. 7, which carries a surprisingly steep advance ticket price of $30, though that includes champagne and T-shirts and other souvenirs. (Call the bar to reserve seats, as they're not expecting to sell any at the door.) Crosby is looking forward to the occasion, as the band and its fans at Flanagan's have a special relationship: Every time Scythian plays Flanagan's, they set a new record for the number of Car Bombs consumed in one night. (A Car Bomb is a drink made by dropping a shot of whiskey or Bailey's Irish Cream into a pint glass of Guinness, and then chugging the mixture.) Last time around, Crosby says, the crowd made it through 177 of them, and this time, he'd like to see the number top 200.

Blues singer Mary Ann Redmond performs in her usual Sunday night spot on Oct. 9, though Nugent expects "some special guests" to stop in during the evening.

The hard part, he says, will be "the last beer you pour, the last walk up the stairs." He and McDonagh joke about how their wives will have to come down and drag them out of the bar, kicking and screaming, holding on to the walls with their fingernails.

"We're going to take a day or two off to recover," Nugent says, "and then we're coming in on Tuesday to move all the satellite dishes over [to the Harp and Fiddle] because we have international [soccer] games on Wednesday," including Ireland against Switzerland and England against Poland.

One door closes, and another one opens.

Patrick McDonagh, left, co-owner of the new bar, and Jesse Mills at the old Flanagan's, which is closing soon.David and Corinne Lease sit at the bar that is the centerpiece of the newly opened Flanagan's Harp and Fiddle in Bethesda.