A school I worked at about 6 years ago did one which was great, but I'm not sure of the finer details regarding the organising of it all. I've got a meeting with my head teacher tomorrow morning and want to try and sell the idea to him.
All I can remember from before was that jobs were advertised and children had to apply. Then it was all carefully timetabled for children to teach other classes and take it in turns working in the office, answering the phones and being the head. It all sounds a bit straight forward (apart from the timetabling bit). Any major points that I've missed?