The House on the Rock
One of the weirdest museums you'll ever see. The house itself is an interesting architectural jumble, particularly the Infinity Room, which is suspended a long way over the forest canopy below. But jaws really start dropping in the second and third areas, which include "The Streets of Yesterday", the world's largest carousel, and more self-playing musical instruments than you ever thought existed. It's a staggering collection of toys, marvels, ephemera and oddities, brought together with an air of mystery and glee. It'd be nice if there were more labels to explain where these things came from, but then it'd take eight hours to see it all instead of four and that's if you move at a brisk pace. Special exhibitions on for the Christmas season.
Taliesin
Once the family home of famous architect Frank Lloyd Wright — and then an architectural commune / school under his direction — "Taliesin" refers both to the iconic house he designed there, and also to the sprawling complex of buildings on the site. Regular performances and receptions are held here, and it's still a working school. There's an inexpensive tour $16, where you'll see exteriors and interiors of the Hillside School. The longer tours, which take you to the interior and gardens of the home, Taliesin, are highly recommended for Wright enthusiasts but pricey $47-$80.