Celebration is the realization of Walt's original concept for Florida. The Florida Project was named EPCOT (Yes that is the same name as the theme park), which stood for Experimental Prototype Community of Tomorrow. Walt wanted to build a planned urban community that blended residential and commercial development in a town setting where families could live, work, learn and recreate. When Walt died, those plans were shelved and a more commercially viable project (WDW) was developed (probably to keep the investors money in the game).
I believe Celebration is on the original Disney land holdings. It is south of 192, off of 417. There is a hospital, golfing, nice hotel, lovely town center and carefully designed and controlled everything. It is pricey, or was when we toured it a few years back.
There are other similar planned communities around the country (at least one is in Florida). Disney brought together a mini think tank of experts on urban design, architecture, education and the like to put the project together. Nicely done in my view.