Happy Hollow Children's Camp takes kids ages 7 to 14 to its 850-acre camp in Brown County, where they get to spend several days swimming, fishing, canoeing, kayaking, foraging, hiking and bike riding.

That statistic is cited in A Swim Lesson, the Oscar-shortlisted short documentary that follows Marsh in the pool as he instructs a new class of tots. For little kids, the 8-day-long process can be ...