4 Parks, 1 Day!

Although I've been to Disney several times, I've never gotten a chance to go to all 4 parks in one day. It's pretty crazy, plus there's no way to do everything. However, I know some people who have been able to go to all 4 parks in the same day and still get plenty done. I've never been to more than 2 - maybe 3 - parks in a day. I think just for the fun of it, I want to plan a day where I can get to all 4 parks and do plenty of things in each of them!