As soon as I saw the title of this thread, Holiday World immediately came to mind.
Also good, but not at the same level as HW, is Indiana Beach...
------------------ --George H ---Superman the ride...coming to a SF park near you soon... Currency tracking experiment... http://www.wheresgeorge.com (Referring to The "George" on the $1 bill - Not Me)
Silver Dollar City. Great theming, fantastic food, really interesting crafts (real crafts, not made in Taiwan or China) and a cave. Throw in Wildfire, Buzzsaw Falls, Thunderation and Fire-in-the Hole and you can have a fantastic day. Really worth seeking out this out-of-the way park.
------------------ Laugh your troubles away at Riverview, the world's largest amusement park.
I'm not sure if most people would agree that it's worth an entire day, but Dollywood certainly has more to offer than just the two great coasters it has. I was only able to spend a couple of hours there, but I really would like to go back and take my time with all the attractions. Frankly, I think I could easily spend a full day there and not run out of things to do. After all, I can reride Tennessee Tornado until I pass out.
------------------ -Vater 'These pretzels are making me thirsty.' Take a ride...
I don't really consider 5 or more to be "few"....but that's me. That being said, I really enjoy places like Miracle Strip where you probably wouldn't want to spend more than 5-6 hours, but at my age that's enough for a day...;) Hopefully I'll add the Myrtle Beach hotspots to the list come April...(Brian, are you there?). Unfortunately, Lake Winnie won't be open for that first foray *up north*...;)
Holiday World and Knoebels are *easy* to spend an entire day at....IoA has but a few coasters and is fantastic...SWO, USF could easily fit in depending on your interests...
I think another park that is easy to spend a day at is Conneaut. Even though there's only 2 coasters(plus the kiddie coaster) they have a good selection of flats and just the atmosphere of the park is great, too.
------------------ Who was the first person to look at a cow and say, "I think I'll squeeze these dangly things here and drink whatever comes out."