Need help with a movie name. The HBO movie featured a group of kids living in a society where it always rains for years and year and one day a year there is sunlight. As a prank, they locked one girl in a room and unfortunately that was the day of sunshine. Anyone know?

All Summer In A Day (1982) (http://www.youtube.com/watch?v=-QWmahMdeGU)

Mr. Hilfiger - you are the man. Thanks