Diamond and gold museum....that should be exciting.
A beaver habitat, with glass cut-aways in the huts so you can see into them. Like an aquarium where you can go through glass hallways under the water and watch them work. Trees they can cut down and live predators like wolves and big cats that they have to protect against.
"The History of Testicles"
A museum of macaroni art...
Earth, Space and Science Museum... because that basically covers anything and everything, so my museum wouldn't be limited and we could just bring in cool stuff, and I think that was the coolest museum I've been in.
One filled with historical spice plants and it would have a restaurant to sell traditional dishes throughout history.
Rock n' roll baby!