At the Magic Kingdom, if you're staying in a WDW resort, and you have a park-hopper pass (I believe, others can back this up / correct me), you can sign up for E-Ride Night. On E-Ride Nights, the MK is open another 2-3 hours after closing, and it's a much, much smaller group of people because it costs more to go.
Essentially, whenever we go, we do one or two E-ride Nights during our stay, and otherwise we don't enter the MK at all. We've been doing it for years, and it's wonderful.