This brings me to my first point.
Superbowl Sunday
Possibly the best day to go, but who wants to miss the game right? It's really a pro and con, the rides are practically empty around mid-day.
Mother's Day
The ultimate day to go if you're an orphan or a goth. Most people are too busy buying flowers and fancy Florida cruises to bother with a theme park.
You could also try days around major holidays such as Christmas and Thanksgiving, most people start family trips around these times and they quickly empty out.
Now, with that said. Time to rant about how mindless people are when it comes to theme parks. I have seen tens of thousands of theme park goers and they all act the same based on who they are. Here comes the racist part.
Stereotypical Black Woman
At least once a week, I see a large black woman between the ages of 12 and 63, lose a small child. Usually due to the fact that she has some type of food in her hand and her kid can't walk fast enough. She then freaks out and screams the child's name about 5 times before realizing he's only 10 feet away.
Stereotypical Asian
Everytime I see an asian at a theme park, he is AMPED. He is pumped up and excited, every picture you can find of an asian at a theme park has that same :D look. It's pretty awesome.
Stereotypical White Guy
There's always some shirtless white guy "hanging out." Asking everyone for free stuff, and possibly selling drugs. This man's theme park experience usually ends in a drunken fight and a flurry of fists as he's escorted back to the parking lot by security guards.
I could go on and on but I've taken up too much time already.