What kind of a song was that rolling out into the snowy air of Ninth Street last night between the Martin Luther King Library and the FBI Building? Listen -- the men's voices are listing five reasons for drinking:

"Good wine, a friend, or being dry,/ Or lest we should be, by and by,/ Or any other reason why." Modesty forbids repeating the words of the next song, about "Sir Walter, enjoying his damsel one night," but the one that followed avoided obscenity if not offensiveness:

"Once in our lives,/ Let's drink to our wives,/ Though their numbers be but small./ Heaven take the best, and the Devil take the rest,/ And soon we shall be rid of them all."

Before long, it became difficult to avoid the conclusion that the National Portrait Gallery had been turned into a tavern. And not merely for men -- a woman's voice could be heard in "Tom Tinker's My True Love," a song that poised again and again on the brink of obscenity.

What was happening was an evening of do-it-yourself song, dance and theatrical entertainment as it might have happened in a colonial tavern with talented clients. Some of the material was quite old-fashioned, dating from the 17th century, but the catches of Henry Purcell and the "Pills to Purge Melancholy" (alias songs) of Thomas D'Urfey never go out of style, dealing with such timeless matters as lust and intoxication. Some instrumental numbers -- expertly played by the Hesperus ensemble -- would not have sounded out of place in a barn dance today, and the fiddle of Tina Chancey and the hammer dulcimer of Scott Reiss would have raised no eyebrows today, though 1980s yuppie couples might wonder at dance music played on recorder, viola da gamba and cittern.

After intermission, the entertainment took on a more professional tone. The Interact ensemble gave a fast-moving condensation of "The Beggar's Opera," focusing on the good part -- Macheath (Daniel Waters) errested; his two wives Lucy (Catherine Flye) and Polly (Nancy Almquist) engaged in a jealous confrontation with Lucy trying to poison Polly; Macheath's long solo (partly sung to the tune of "Greensleeves") while contemplating death on the gallows, and his last-minute release to the tender intimacies of his polygamous household.

Even without the remarkable three-legged dance of Charles Garth, it would have been a memorable evening.