Mum found Jack an advent calendar that was right up his alley. It had pictures of Thomas (the tank engine) and behind each door was a chocolate. Perfect.
I guess the problem was that I forgot about it till the third of December so when I produced it and explained the concept of opening it one day at a time (ie one piece of chocolate a day) I spoiled this somewhat by then giving him three days worth in one sitting. We went okay for a few days and then all hell broke loose. All thoughts of Thomas were thrown out the window as the cardboard was ripped and the chocolates revealed and a fair number consumed before the whole sticky thing was removed. There's always next year.