Shared Universe/ Sitcom stars TV Movies

I saw the spin-off post and it brought to mind the shared universe some sitcoms shared. Example.

Murder She Wrote and Magnum PI

Also, does anyone remember. It was usually in the 80's early 90's before summer break was over, there would be a made for TV Movie starring sitcom stars in one movie. There was one with Micheal J. Fox and another one about a summer camp?