I remember Disney World. We went almost every summer, right when it was the most uncomfortable time, heat-wise
We had a blast anyway. Our favorite park would have to be Magic Kingdom, because a good number of rides are concentrated there. Animal Kingdom is more like a petting zoo, although it has some pretty epic rides as well (Expedition Everest, Kali River Rapids). Epcot is almost... educational... at times. It has lots of indoor things, and some shows. We watched Chinese acrobats in "China," a candy artist demonstration in "Japan," and an acting troupe in "Italy" perform one of the most hilarious, butchered renditions of Romeo and Juliet I've ever seen

An indoor shop (read: air conditioned) is always nearby. It's normally selling overpriced merchandise, but hey, they have to pay for that wonderful, freezing air somehow

Epcot also has a few cool rides: Mission Space, Soarin', and Test Track. The lines for these tend to be a bit ridiculous, though

The final park, MGM Studios, has a zillion awesome shows. Indiana Jones Stunt Spectacular, Star Tours (kinda a ride, but w/e), Studio Backlot Tour, (also kinda a ride), and
especially Lights Motors Action are things we've gone to again and again. It also has Twilight Zone Tower of Terror and Rockin Roller Coaster, both of which are top-tier rides.
There's water parks too, but we don't usually go to those.
Some of the hotels are almost parks of their own. The Beach Club has an epic pool that's essentially a miniature water park. The Boardwalk has carnival games, fried dough, magicians, stuntmen, etc (mini carnival). The Animal Kingdom Lodge has a freaking "wildlife preserve" attached to it (mini zoo).
... Haven't stayed at any of the other hotels (and/or there isn't anything freaky-awesome about them), but yeah.
Disney was always fun for us.
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