I'm not sure whether I'm happy or sad about this, but in three days, the 1980s will be half over. While I'm making up my mind about which kind of greeting January '85 deserves, let's usher in that new month the way we always do hereabouts_with Bob's Bulletin Board, a summary of what's upcoming around these parts in the two fortnights ahead.

VEGETARIAN POT LUCK SUPPER AND LECTURE, Jan. 1

Guy Mason Center, 3600 Calvert St. NW, 7 p.m. Sponsored by the Vegetarian Society of D.C. Further information: Madge Darneille (949-VEGY).

MESSIAH SING-ALONG, Jan. 12 -- Reorganized Church of Jesus Christ of Latter-day Saints, 3526 Massachusetts Ave. NW, 7:30 p.m. Admission free. Further information: Sandy Johnson (966-0751 or 279-3146).

MUSICAL COMEDY AUDITIONS, Jan. 5 and 6 -- St. John's Episocpal Church, 3240 O St. NW, 10:30 a.m. to 6 p.m. Jan. 5, 1:30 p.m. to 6 p.m. Jan. 6, for "Thirty Proof," annual production of Hexagon Inc. Actors, singers, dancers, production staff needed. Further information: Skip Maraney (543-1661).

LAMAZE CHILDBIRTH COURSE, beginning Jan. 20 -- Sponsored by Reston Medical Group, 11305 Sunset Hills Rd., Reston. Classes run for six consecutive Sundays, 7 p.m. to 9 p.m. each week. Fee is $60 per couple. Further information and registration: 435-2227.

ANTIQUE SHOW AND SALE, Jan. 16-19: Sponsored by The Woman's Club of Bethesda Inc., 5500 Sonoma Rd., Bethesda. Hours are 11 a.m. to 8 p.m. the first three days, 11 a.m. to 6 p.m. the last day. Admission $2. Proceeds go to local charities. Further information: Carolyn Evans (530-0690).

BOOKBINDING WORKSHOP, Jan. 20 -- Jewish Community Center of Greater Washington, 6125 Montrose Rd., Rockville, 1 p.m. to 3 p.m. Open to third graders and older. Preregistration required. Further information: 881-0100.

OPEN HOUSE, Jan. 10 -- Burgundy Farm Country Day School, 3700 Burgundy Rd., Alexandria. Hours are 10 a.m. to noon and 4 p.m. to 6 p.m. Further information: Sally Scott (960-3431).

HERPES SUPPORT GROUP, Jan 8 -- Sponsored by National Hospital for Orthopaedics and Rehabilitation, 2455 Army Navy Dr., Arlington. Group covers medical and psychological aspects of herpes. Registration confidential. Further information: 920-6700, extension 4330.

ORIENTAL BRUSH PAINTING EXHIBIT, Jan. 7 through Jan. 29 -- Sponsored by the Sumi-e Society of Washington, 3401 Fairfax Dr., Arlington. Hours are 9 a.m. to 9 p.m. daily. Further information: Helen Remington (527-9087).

COMMUNITY THEATER, Jan. 11, 12, 18, 19, 20, 25 and 26 -- Fairlington Players' production of "Come Back to the Five and Dime, Jimmy Dean, Jimmy Dean," 8 p.m. every day except Jan. 20 (curtain that day 2 p.m.), Gunston Arts Center, 2700 S. Lang St., Arlington. Admission $5 (students and senior citizens $4). Further information and reservations (549-0558).

Bob's Bulletin Board appears on the final Friday of each month in Bob Levey's Washington. Contributions are welcome. There is no charge. Submissions for the Jan. 25 edition are due by Jan. 18. Please send items in writing to Bob Levey, The Washington Post, Washington, D.C. 20071.

Well, I guess you can't lose 'em all.

Earlier this month, I wrote about a fellow named Dennis Butler. I first encountered Dennis when we hooked up to try to poke a hole in a silly policy of the American Red Cross.

The policy set an arbitrary age limit of 66 for blood donors. If you were older than that, they didn't want your red stuff, regardless of how healthy you were.

But in September, writes Lucy Srabstein, a public education specialist at D.C. Red Cross headquarters, the age policy was dropped. "Blood donors beyond the age of 66 may continue donating indefinitely as long as they continue to meet all other standard blood donor health requirements," Lucy says.

Thanks for listening, Red Cross. And an equal tip of the chapeau to the gang at Potomac Electric Power Co.

I took a slice out of that well-known local utility a few days ago when a reader discovered that you couldn't give cash to the Washington Area Fuel Fund at Pepco headquarters on Pennsylvania Avenue. Reason: No one there was authorized to accept it.

Nancy Moses of Pepco called to say that, as of Dec. 19, the cashier in Pepco's lobby has gotten all the authorization a cashier could ever need. Thanks, Nancy. Thanks, Pepco.