http://www.campeberhart.org/main.htm I went here 4 yrs in a row as a kid. Has a fantastic observatory. On a side note, I met my very first girlfriend there... only one who hasn't broken my heart.
Here is a camp we sent my son to for several years. All types of activites (old Time Summer Camp Type Programs) Run By a teacher who has been doing this every year since chilkdhood. His family started it many years ago. http://www.forestlakecamp.com/
Here's a good one across the lake from me. My wife worked there as a college student. She also grew up here, and now we raise a family here....It is a great place to be in the summer time. phil