THE LIBRARY OF CONGRESS schedules events for the public year round. They range from the Juilliard String Quartet playing the Strads, to poetry readings, to hourly guided tours. Here's a sampling of concerts coming up in the Jefferson Building's Coolidge Auditorium, said to be acoustically perfect: CONCERTS

SUNDAY CHAMBER MUSIC -- with the U.S. Marine Band, this Sunday at 3, and January 13 and 27; and February 3, 10, 17 and 24. Free; no tickets required. Call 433-4011.

HANDEL & BACH -- The Aulos Ensemble plays period instruments, February 1, at 8. Tickets required; distributed the Monday before the concert by the Washington Performing Arts Society at Jordan-Kitt's, 1330 G Street NW, beginning at 8:30 a.m. Phone reservations may be made at this time, 393-4463. Two tickets per person; the only cost is a 25-cent service charge on each ticket.

BEETHOVEN -- With the Beaux Arts Trio, on February 8, 21, 22 and 28, at 8. Tickets required. See above for distribution. MOVIES

For the next three months, the Mary Pickford Theater is celebrating British comedy, slipping in a few silent classics. On the third floor of the Madison Building; admission is free, but seating is limited to 64. Phone reservations are taken starting a week before the show. Call 287-5677, Monday to Friday, 8:30- 4:30. Movies start at 7:30, except where otherwise noted. This month's schedule:

ONLY TWO CAN PLAY -- Peter Sellers stars, January 9.

THE WHITE BUS -- with Patricia Healey and Arthur Lowe; and "Morgan," with Vanessa Redgrave, January 11.

THE MAN IN THE WHITE SUIT -- with Alec Guinness and Joan Greenwood, January 15.

BUTLEY -- with Alan Bates and Jessica Tandy, January 17.

THE GREEN MAN -- with Alastair Sim and Terry-Thomas, January 21.

NAPOLEON -- silent film directed and written by Abel Gance in 1927, January 24 and 25. Showtime, 7 p.m.

WHISKEY GALORE -- with Basil Radford and Joan Greenwood, January 30.