Check out the Budapest Pinball Museum, featuring over 150 pinball machines!

[grenadier]

Yes, they are permanent exhibits.

Fun Fact: The Strong National Museum of Play is the only museum in the world that is achieving video game concept blueprints. Most of them have been lost over time, but they have received a few directly from Sega and Nintendo.

Yeah, they keep posting about notebooks and other development materials that developers have been donating. That kind of thing is usually not on display for the public, and is mostly available to researchers, students, and collectors by appointment only. Companies have been doing the same as well, so it's turned into quite the archive of stuff.