For sheer excitement last Sunday afternoon was hard to beat.

All those participants in blue and white and burgundy and gold, keyed up, anxiously trying to do their best. And the keyed-up crowd, sounding its approval.

For the several hundred people at Bradley Hills Presbyterian Church in Bethesda, however, it wasn't the soaring passes of Joe Theismann that made their insides flip. It was the soaring soprano descants. And it wasn't the fierce competition that kept them on the edge of their seats. It was the glorious harmony.

Taking place at exactly the same time as the Big Game, the big sing brought members of four Bethesda churches together in a mighty muscial celebration of the season.

Choir members for an adult and children's group came from the Little Flower Roman Catholic Church, the Bethesda First Baptist Church, the Christ Lutheran Church of Bethesda and the Bradley Hills Presbyterian Church. Altogether, seven conductors and organists shared playing and directing responsibilities.

Everybody had a chance to join in the fun. Audience participation in familiar carols alternated with the singing of less familiar carols by the children's and adult choirs.

Midway there was a thundering organ solo, just in case anybody's interest was flagging.

The driving force behind this ecumenical caroling bash was Donald Sutherland, organist and director of music at Bradley Hills Presbyterian Church. Sutherland got the idea from his experiences in London during the 1977 Christmas season, when he was on a sabbatical and his wife, singer Phyllis Bryn-Julson, was on a cultural fellowship. They decided to take their two children to the famous London Bach Choir family carols, which are held every year on two successive Sundays in December, and always sold out.

"It was one of the most thrilling experiences I've ever had," recalled Sutherland. "There we were, in the midst of 8,000 people in Albert Hall, singing Christmas carols with the London Bach Choir. I was literally overwhelmed."

Back in the United States at his Bradley Hills Church for the Christmas of 1978, Sutherland started his own version of a community carol sing with the Little Flower Roman Catholic Church.

At end of that program his 10-year-old son David wanted to know why only adults were allowed to take part. Sutherland answered the question by putting together a children's choir for this year's carol fest. David and his 6-year-old sister Karen both sang in that choir.

Sutherland is already thinking about bigger and better plans for the coming year.

"Next Christmas we're going to have brass playing from the balcony!" he said, with all the enthusiasm of a child who has just discovered that Santa Claus exists.

As Christmas Eve approaches one fact is clear. Audiences from the Big Sing are feeling a lot merrier than those from the Big Game.