Three companies (Voyager Expanded Learning, Mindsurf, and EXPLORE) have introduced after-school programs that emphasize stress-free academic enrichment activities. The companies differ, but share a fun-learning concept, maintain low staff-child ratios of about 1:8, and serve grades K-8. The operative words are flexibility and affordability. Some critics worry that kids may not be getting enough exercise or unstructured time. (MLH)