Several valuable items, including an Arabian colt, will be sold at auction beginning at 8:15 p.m. Saturday at Marymount College in Arlington. An item in the Virginia Weekly's Bulletin Board yesterday said incorrectly that the items were to be sold earlier in the day at a silent auction.

*The Arlington Bar Association is sponsoring a "Law Day" seminar for the elderly on May 1 that will cover such topics as age discrimination, crimes against the elderly and wills and trusts.

The seminar, planned in conjunction with Legal Services of Northern Virginia, will be held from 10:30 a.m. to 1:30 p.m. at Culpeper Gardens, 4435 N. Pershing Dr., Arlington. State Sen. Edward M. Holland will be the keynote speaker. The seminar is free.

*Marymount College will hold its gala Angels' Auction on the campus at 2807 North Glebe Rd., Arlington, this Saturday from 6 to 7:30 p.m.

The silent auction, called by auctioneer Paul Berry of WJLA-TV, will offer prizes like an Egyptian Arabian colt, a trip on the Orient Express from London to Paris, weekend getaways, Redskins tickets, a White House luncheon, a collector's mechanical bank and original artwork for handwritten bids. After dinner at 8:15 p.m., the bidding will begin for the larger, more valuable items.

This is a major fund-raising event for Marymount, and several local celebrities plan to attend. For information or reservations, call 522-5600, ext. 200.

The Alexandria Department of Recreation, Parks and Cultural Activities' Recreation Class Program has scheduled many one-time "sampler" workshops in areas of public interest or as introductions to full-length recreation classes. Samplers scheduled for this month include: free tennis clinics, a tumbling-gymnastics preview, estate planning, creole cooking, a "gymboree" open house, a fencing demonstration and astrology. Advance registration is required due to limited space. For more information, call 838-4831 or 838-4834.

*The Old Dominion Ballet Theatre presents "The Seasons" by Alexander Glazunov and "Chopin Mementos" on April 26 at 8 p.m. They will be performed at the Alden Theater, McLean Community Center, 1236 Ingleside Ave. For tickets or further information, call 790-1172 or 821-3248.

*The book discussion group sponsored by the Friends of the Arlington County Library will meet on Monday, April 28, at 8 p.m. at the Arlington Central Library, 1015 North Quincy St. The book discussion will focus on "Lee and Grant," a Civil War biography by Gene Smith. The monthly program is free and open to the public. For more information, call 284-8181.

*Ay caramba! Come to a Mexican fiesta with unlimited buffet and homemade desserts at Trinity Church, 2911 Cameron Mills Road, Alexandria. "La fiesta" will take place Saturday, April 26. There will be two seatings: one at 5 p.m. and one at 6:30 p.m. Expect strolling musicians and a candlelight atmosphere. Tickets are $8 per adult and $4.50 per child under 10 years. Reservations are required. For more information or reservations, call 549-5500.