Bekonscot is somewhere that I have heard about since I met my wife nearly twenty years ago, but having not been brought it in the south of England, I had never visited the place as a child.
For those that do not know Bekonscot, it is, if I am not mistaken, the largest model village in the world. Whilst some of the parts are a little old, I am sure for all of the parents returning for the first time since they were themselves kids, they can probably be classed as nostalgic. 
The village is laid out so that you follow a path through the town, starting at the cricket pitch, past the zoo, and around the airport, hotel and fair. With many more little areas of interest.
Having chased the model trains around the park all morning, it was equally exciting for the boys to ride the miniature railway.
We took a break from visiting the village to have lunch and play in the park.
Our boys have been here several times and I know that most of our friends children have been here many times (probably once a year), so I expect that we will be back again in the not too distant future. As a charity Bekonscot give all profits away, so its also another good reason to visit.
Bekonscot Model Village – Beaconsfield, Buckinghamshire, HP9 2PL
http://www.bekonscot.co.uk/