Technology Museum Sinsheim and Speyer
Well… they are officially called a museum, but to be honest… you should see it more as a huge collection of everything that has anything to do with technology (and sometimes not). Tanks, pipe organs, cars, chainsaws, a camel, trains… That's it. Definitely worth a visit, take at least one day per location for your visit.
And yes, these are two museums, which are close to each other and have the same scope. You can also buy a combination ticket, but… allow two days for it and don't try to visit both in one day. See https://speyer.technik-museum.de/and https://sinsheim.technik-museum.de/ for more information.