THE KIDS probably lured you, on a lazy midsummer evening, to a cool theater to see one of the season's better Hollywood offerings, "War Games." Adolescents love the story not only because it centers on the kind of whiz-bang home computers they all covet, but especially because the hero, a bright but lazy 16-year-old left entirely to his own devices by preoccupied and bamboozled parents, manages to use his computer to put one over on the high school principal, win the affection of the coolest Valley Girl in class and save the world from nuclear holocaust about to be caused by dim-witted adult generals, scientists and world leaders. President Reagan, who saw the movie at a special White House screening early this summer, liked it, too.

Well, if you thought this high-tech plot was just a diverting summer fantasy, think again. Perhaps inspired by the movie, in which the hero uses his home computer and a telephone to break into the secret Pentagon doomsday computers, a group of 15- to 25-year-olds in Milwaukee, using their own hard and soft ware, managed to gain access to unclassified information stored in a nuclear weapons lab computer. This kind of invasion of someone else's computer is against federal law, but apparently the Milwaukee youngsters had no criminal intent. They just liked the challene involved in breaking the code and getting into a system. It's not hard to do; in three cases they found that the key granting access to secret information was the use of the imaginative password "system."

No harm seems to have been donper, and some good may come of it. Defense and scientific experts have been jolted by the realization that teen-agers can crack supposedly confidential systems; they have scurried to improve security. And Milwaukee school administrators, while publicly disapproving of the adventure, are entitled to a little private satisfaction. Some of the youngsters in the group have been enrolled in a special computer training program at a public high school, which has obviously been successful beyond their teachers' wildest dreams.

Those of us over 35 who are still computer illiterates have cause to worry about how we will raise children who are not only comfortable but ingenious at a keyboard and screen. The true generation gap is between ngsters who are growing up with computers and parents who are intimidated by them. Sad to say, the distance iss of the floppy disc and aging masters of the curve ball.