For the second summer in a row a friend and I have "run" a program that we call "Summer Strings." We meet once a week during about 8 weeks of the summer, and we play music. The general favorites are pieces by Handel, Vivaldi, and Mozart, but we also mix things up with arrangements of show tunes and music from movies. Since there is not that much music for string orchestra that is accessible to younger kids, we play a lot of "custom" arrangements (in other words, quartet arrangements I have made over the years) of pieces. We have unwritten and unspoken guidelines for our group: anyone of any age and any playing level can come and play, nobody is required to come, it doesn't cost anybody anything (the local arts council gave us money for photocopying) anyone can sit wherever he or she wants, nobody practices the music (they can't--it stays in the place we play), anyone can make comments and tempo suggestions, and we do not have a conductor.
At the beginning of each summer things are a bit rough. People are shy and a bit insecure. By the end of the summer we have real music making. Without having to be told in any way at all, the people who participate in Summer Strings know the social and musical rewards of practicing, and they learn the joy of playing music in a situation that is totally devoid of pressure.
I'm really looking forward to next summer.