Before I became an AP holder, I had never previously entered the park any later than around 3:00 PM on a one day visit due to the cost. Now that I have an AP, we were in the area the other night and decided to stop in just after 8:00 PM and stayed until 11 or so. It wasn't too busy (Sunday), so ride times were short and we got to see the fireworks. It was fun -- we normally go in the AM but don't stay until night time. We'll probably do it again sometime.
What's the latest time you've entered the park for just a one day visit?