For many American kids, summer is a time filled with activity – trips to museums, sports camps, and swimming pools. But those activities aren’t available to millions of lower-income kids. For them, summer vacation means something quite different: academic stupor and an attendant loss of educational gains made during the school year.

This so-called “summer slide” affects most kids – on average students lose one month of academic progress each summer, according to a RAND report published this year.

But the effect is much more dramatic on lower-income students, resulting in an ever-widening achievement gap between them and their higher-income peers. Karl Alexander, a Johns Hopkins University sociologist, determined that by ninth grade, summer learning loss accounts for two-thirds of that achievement gap in reading alone.

But, there are ways to stop the backslide. Last week, we interviewed kids who are enrolled in a summer learning program – part summer camp, part academic camp, but designed so as not to have the same level of appeal as a dread summer school.

We asked one of the boys at the program, Horizons in Rumson, N.J., what his friends were up to this summer while he is at camp.

“They’re probably home watching TV, hanging out with their friends, being outside,” Kevin Paz, 12, said. “The only difference is that we’re learning more when they’re just having fun.”

These types of “summer enrichment” programs have cropped up nationwide, and they are providing an alternative to summers filled with flickering screens and little else. But they come with price tags of several thousand dollars per child, according to the RAND report, requiring a fair amount of fundraising.

This week on The Learning Curve, we’ll take a closer look at Horizons National, we'll ask five questions of Karl Alexander, and we’ll hear from Earl Phalen, the founder of Summer Advantage in Indianapolis, and Matthew Boulay, CEO of the National Summer Learning Association.

Stay tuned.

All statements and opinions expressed on this blog are those of the individual contributors, and not of the Bill & Melinda Gates Foundation or NBC News.