This very small theatre located in a strip mall in Roswell, GA has a summer series for kids. I took my 4 year old and 2 year old for the first time, on a recommendation from a friend, to see Rumplestiltskin. To my surprise, they loved it!
It was a show put on entirely by teens getting their feet wet in theatre. While I found the acting to be just what I described - teens getting their feet wet in acting - my kids loved it. The length of the show was just to their attention span, about an hour (with an intermission).
The tickets were $8.75 per person...no price break for children (which can make it expensive). But, you are allowed to bring snacks into the show which helps the children make it through.
This theatre is also conveniently located near several fast food locations includinga Chik-fil-A which makes for a perfect end to the morning.
Check the website for show listing and times as they change seasonally.