Kumon Learning

Kumon is a program that brings together students of different ages in a learning-assistance organization. Older students - typically in high school - serve as teachers and provide help to younger children with their homework and assignments, in an effort not only to further the development of the younger child, but to expose students of different age groups to each other. This is meant to reduce prejudices - or fears - that these students might normally have in interracting with each other on a more casual basis, such that a younger child might more willingly go up to an older one to ask for help, or even just to simply play.
I had a number of friends back in high school who were part of this program, and nearly every account I got from them was a positive one. Stories about how they were meeting great kids who really wanted to learn, or about how proud they felt once they'd helped these children through a difficult problem, were inspiring, and made the program, from what it sounded like to me, very worthwhile. A couple of them even told me about how they would get calls from individual students off-hours asking for help, which is something that I as a child, who had never participated in a program like this one, would never have done.