You don't have to be Episcopalian to entertain your children at the Washington Cathedral on Saturday. Whatever creed your kids are espousing these days, there's free entertainment there for them from 9:30 a.m. to 5 p.m.

It's the cathedral's 70th birthday, and this year's celebration includes a festival to be enjoyed by the entire Washington community. After all, it's long been a tradition for people from all over the city to get their plans at the cathedral's shops, even if they then go elsewhere to pray for the plants' welfare.

It is only twice a year, on this occasion and during the cathedral's spring fund-raising Flower Mart, that is valuable merry-go-round is in operation. Vintage merry-go-rounds ceased to be merely large toys and became objects of art a few years ago, and the cathedral's 1892 Dare is well known among connoisseurs. Nevertheless, the discriminating child and the far-more-common non-discriminating variety can ride it Saturday for 35 cents.

That is the only attraction at the celebration for which there is a charge and there is no admission fee. Music, dance and puppet and mime shows are scheduled throughout the day.

These include the St. Andrew's Society Highland Dancers and Pipers and Drummers performing Scottish folk music and dance, Craig Babcock doing mime, the Trinity Puppet Theater with stick puppets in Bible stories and the Heartspring Dance Drama Company in "The Soul Embraces God." Most of these are in the early afternoon.

At 4 p.m., there will be music from the Cathedral's Choral Society, Choir of Boys and Men and Schools Glee Clubs and the St. Paul Choir from Akron, Ohio. At this time, there will also be free birthday cake, as long as it goes around. The cake is to be baked in a shape that is to be a surprise, a cathedral spokeswoman said, although a good guess might be made by observing whether the residents stone-carvers are now working in icing.

The stone-carves will be demonstrating their skills during the day, and so will the volunteer workers who make needlepoint cushions for the cathedral and arrange the altar flowers. This might be in the older-child department, along with the tours being given all day. A minimum age of 9 has been set for those who want to climb the tower. This is a rare Washington tourism opportunity - the central tower is the highest point in Washington and not open the rest of the year - but recommended only for the hearty. You get some pauses and intermittent elevator assists on the way up, - 10 flights of stairs - and no help coming down.

In the way of older-still, or adult entertainment (in usage of that word as before it came to mean entertainment not provided by cathedrals), there will be morning lectures on stained glass and on architecture. There are no specific day-care sections where you can park children while listening to lectures or shopping in the Herb Cottage, greenhouse or gift shop, but there is a large, traffic-free space relatively safe for a free-roaming child.

It also makes good picnic ground, and visitors are encouraged to bring their own lunches, although hot dogs and Cokes will be sold.

You might also want to know that there are large banks of bathrooms in the northwest corner of the cathedral.