A saint prayed to God for a blessing: "Give me the heart of a child and the courage to live it out." Beginning today, the prayer might be altered slightly: "I have the heart of a child, give me the awesome courage to play it out." Some of that childlike play, springing from God-pleasing courage, will be on display this afternoon when some 5,000 mentally retarded athletes from 70 countries and every state will be at Notre Dame stadium, South Bend, Ind., for the opening ceremonies of the Special Olympicssummer games. They will be led by a Greek delegation, including Margaret Papandreou, the wife of the prime minister.

Through this week, the presence of the athletes, as well as the 1,500 coaches and 15,000 volunteers, means that this is the largest sports event for the handicapped ever held. It is the largest amateur participatory event in the world this year. Heroes -- the real kind -- are coming to Notre Dame.

The size of this summer's Special Olympics is proving irresistible to the media. Sports Illustrated, which has not covered the previous five international games, is at last recognizing the event as an athletic competition by sending a team of reporters and photographers. On Monday evening, ABC will give two hours of televised coverage, the first time a network has thought the achievements of the mentally retarded worth two hours of prime time.

Cameras and reporters are the reliable Greek chorus to this olympiad where stopwatches catch times but not desires. But the definitive story of the Special Olympics has yet to be written. It is a revolution in progress. The idea began in the mid-1960s when Eunice Kennedy Shriver organized a summer day camp for a few mentally retarded children. What could have remained a day in the country, followed by a ride back to a center, an institution or a shelf, became a social movement that no one, least of all the experts and seminar holders, foresaw.

The idea of athletic competition for the mentally retarded -- as a therapy, as a joyful twisting of fate's tail -- was unknown. Shriver, a woman gifted in her dissatisfactions with the ordinary, has been confounding the experts since. She has been conducting a global seminar on behalf of the world's 300 million mentally retarded: "In a world where poverty, war and oppression have dimmed people's hopes, Special Olympians rekindle that hope with their spiritual strength, their excellence and achievements. For as we hope for the best in them, hope is reborn in us."

News stories about the Special Olympics, as state and local programs are held throughout the year involving 1 million Americans and 300,000 people abroad, often have a sugarized tone, as if this really isn't athletics and as if the games are frolic not to be taken seriously by anyone who matters. Those who look on the program as too sweet by half ought to get on a track and try to equal the quarter-mile run in 85 by John Canning, or in a pool and swim 100 meters in two minutes as did Wendi Little, or in a gym and match the 200 pounds bench-pressed by Pablo Antionini.

At Notre Dame this week, the average age of competitors is 23, up by four years since 1983 when the event was held in Baton Rouge, and up from age 15 in Chicago in 1968. The rise in age represents an increase in community involvement for the mentally retarded who are out of school or can no longer live at home. The feared question of families with retarded children -- who will look after them when they are grown? -- is partially being answered by the Special Olympics: They will look after themselves. The self-confidence gained through athletic training and competition carries over into the rest of life.

Much else carries over, too. In 20 years, the Special Olympics has set outdoor records for the improbable anecdote. Among them is the story of the 1985 European games in Dublin. When the delegation from Belfast paraded in front of the reviewing stand, the filled stadium erupted in cheers. The Special Olympics is the only activity that communities in Ireland and Northern Ireland do together.

Another "only" involves the presence of Cui Naifu, the minister of civil affairs of the People's Republic of China, on the Special Olympics board of directors. It's the only time that a cabinet minister of the Chinese communist government has been officially associated with an American program. The Peace Corps is not in China, but Special Olympics is. Another board member from a communist country is professor Jerzy Doerffer, a Pole and former president of the Technical University of Gdansk. He has a retarded child and helped bring the Special Olympics into Poland.

None of this was imagined two decades ago. What chance did a program about caring, love and friendly sports competition among the handicapped really have of becoming a global presence? A small chance, which is why the story of Special Olympics 20 years later is something more than a sentimental tale. Ask the families. Ask the athletes.