"You've probably heard this song before. Me too," deadpanned Arlo Guthrie as he launched into a slightly revised and, believe it or not, longer version of "Alice's Restaurant" Saturday night at Wolf Trap. Meanwhile, Pete Seeger, taking his cue from the crowd on the lawn, stretched out on the stage floor and listened while Arlo zealously recounted his fabled run-in with the law.

If "Alice's Restaurant" was the evening's most requested song, it was by no means the only favorite. Nostalgic, amusing and sometimes inspiring, the concert was filled with them.

Seeger, a living repository of folk songs if ever there was one, had no difficulty coaxing the crowd to sing along with him whether it be "Midnight Special," "Turn, Turn, Turn" or an unfamiliar song from Argentina. Though he accompanied himself mostly on banjo and 12-string guitar, Seeger played a touching love song on a wood flute, which he dedicated to his wife Toshi. Saturday marked their 42nd wedding anniversary.

For his part, Guthrie engagingly recalled many of his better known songs and a couple by his father, Woody. And, as expected, "Motorcycle Song" and several other tunes were punctuated by feverish digressions of epic proportions.