THE Indianapolis "500" is much more than merely the best known automobile race in the world. It is a cherished time-honored institution with a glorious history dating back more than one hundred years. Known to most as, quite simply, "The 500," it has been held every year since 1911, the only exceptions being 1917-18 and 1942-45, during the periods when America was involved in the two world wars. Steeped in tradition, it has meant many things to many people and has played an enormous role in the lives of human beings, perhaps even more so for the spectators and devotees than for the participants themselves. For over half a century, Memorial Day meant either trekking to the track or else ensuring that whatever other activity was planned for the day, a radio would always be within earshot.