@TonyTib, oh, we love Deutches Museum in Munich! Every time when I used to cover Electronica in Munich, I secretely plotted my travel plan so that i could set aside a weekend to go to Deutishes Museum (and Christmas Market at Marienplatz)!
If you are likely to go to several science based museums (especially if there is one local to you) consider getting a membership to one of them. Many offer discounts to members of related museums.
I can attest to the appeal to kids of all ages for this one. A few years ago I went to the City Museum while in St.Louis for the FIRST World Championship (Robotics competition). Our group had 3rd through 11th graders. They all put it at the top of their list for favorite part of the trip outside the competition. It is a bit more playground than many museums, but some experiences are best when you get your hands dirty...
COSI (Columbus, OH)
I gotta put a plug in for the one near me. If you are in Central Ohio COSI is worth checking out.
It need not be huge museum. What is required is small Community Science Center with equally active and creative curator.
Weekly (weekend( small workshop with hands-on approach is more effective. The theme and display articles can be elf created or can be moved around chain of these types of center around country. It may need more volunteers.
It's nice to know money isn't a problem for you, but for most of us those admissions price are substantial chunk of change, and not very kid friendly (especially since kids get tired pretty quickly: my rule is 2-3 hours max, so 2 visits of 3 hours is much better than 1 visit of 6 hours)
I frankly don't care what they charge, but it affects my decisions. That's why I haven't been to the Monterey Bay Aquarium in over a decade (it's nice, but overrated, and not worth it - for the same price I'd rather go to the Cal Academy). So if they want fewer people to visit, fine.