A Scrooge-like Uncle Sam may have refused them their traditional Christmas Eve holiday, but thousands of federal employes took the day off anyway yesterday, many of them using annual leave. Of those who reported to their jobs -- somewhere between one-third and one-half of the work force, according to a random survey -- the luxury of hassle-free parking on the street and whole hours without the intrusive ringing of official telephone calls made coming to work almost a pleasure.

From the Architectural and Transportation Barriers Compliance Board, a tiny federal agency in Southwest, to the giant Veterans Administration across town, the story was the same: a morning of pleasantly underpopulated offices that stretched into a lazy afternoon of worker-free zones.

"Normally, this place is alive with 2,000 people, but we have half that number now," said Veterans Administration spokesman Don Smith shortly before 1 p.m. "Things started off slow and are tapering off to the bare minimum."

A spokeswoman for the barriers compliance board reported that only 10 of its 30 employes had reported for duty. "Even the director is out for the holidays and said we could take several hours off at the end of the day," she said.

That leave at day's end was, in effect, a bonus for those complying with a Dec. 3 order from the Office of Personnel Management to work on Christmas Eve. The day had been a holiday under presidents Nixon, Ford and Carter.

OPM Director Donald J. Devine said a full holiday for all employes would have cost the deficit-conscious federal government $223 million, the amount of its daily payroll. But supervisors were encouraged to allow their employes to leave three hours early, at 1:15 p.m.

"It was never a question of whether you come to work or not, but of who was going to pay for it -- the taxpayer . . . or the employe who took annual leave," Devine said during a full day of television interviews and paperwork. Taking his own directive to heart, Devine said he planned to work "oh, till 5 or 6 o'clock."

Others, though, abided by the bureaucracy's time-honored maxim governing vacation time: Use it or lose it. At OPM's public information office, for instance, 11 of 16 employes took annual leave to escape their Monday rigors, said agency spokesman S. Mark Tapscott. Tapscott estimated that at least one-third of the 350,000 federal workers in the Washington area took annual leave yesterday, adding that the number could increase when final pay reports come in.

U.S. Postal Service employes, virtually barred from taking annual leave in the week before Christmas, naturally were at work in force yesterday. "This is the heaviest day of the year for our carriers," said Gerald F. Merna, manager of the giant postal complex at Merrifield in Fairfax County, which cancelled a record 2.1 million pieces of mail in a single eight-hour shift last week.

For the 1,200 city and rural carriers plying the sidewalks and country lanes of Northern Virginia, "annual leave requests are really scrutinized this time of year," Merna said.

"You get it only for really approved reasons" of hardship, he added.

At the State Department, whose employes also are accustomed to round-the-clock shifts, Thomas Longo, the desk officer for Italy and Malta, spent the day monitoring recent events in those two countries.

"I'm surprisingly busy," said Longo, referring to the terrorist explosions on a train near Florence on Sunday and the resignation of the Maltese prime minister the day before.

Longo, who was scheduled to work until 6:45 p.m., said his department was "decently staffed. If something happens, you've got to have people here to handle it."

Meanwhile, at the White House, spokesman Robin Gray said the staff was "not up to full swing, but is fully functional." Only three people in the 10-person press office were on leave yesterday, he added.

Mostly functional -- at least for half a day -- were dozens of small state and local agencies in Maryland, Virginia and the District. Prince George's County government offices were closed, as were those in Fairfax County.

At the courthouse in Maryland's smallest county, Kent, in Chestertown, Circuit Court Clerk Earl H. Pinder said he was "mopping up," signing papers and sifting through land deeds, before he left at 1 p.m.

After a day when there were no court hearings, the early departure time "works out pretty well and keeps everybody happy," Pinder said.

Similarly, the District's Department of Consumer and Regulatory Affairs maintained a skeleton crew yesterday at its H Street NW offices and allowed some workers to leave early. "The thing I've noticed most is how unusually quiet the phones have been," said spokeswoman Joyce McCray. "It's finally given me a chance to catch up on some paperwork."

An equally relaxed atmosphere pervaded the Fifth Street NW headquarters of the Washington Metropolitan Area Transit Authority, where spokesman Al Long took advantage of the slow day to escort a television crew to a subway station, edit a newsletter story and fill out his colleagues' time sheets.

"Everybody's relaxed and ready for Christmas," Long said. "I'm actually getting work done because the phones aren't ringing."

The public sector held no monopoly on pre-Christmas leisure. The Virginia Electric and Power Co. was among the host of large local corporations which gave workers the day off. Vepco maintained emergency crews on a standby basis during the day, but gave most of its 1,300 employes in Northern Virginia a holiday because "it made good sense to do it," said James Buck, a company official.

Scheduling work on a Monday one day before Christmas "would have made planning tenuous," Buck said. "We would have experienced a high number of people who would have just taken the day off."