If you ever visit San Francisco with kids, The Exploratorium on Pier 15 is an absolute must. By no means a cheap date at $100 per family, but it is certainly a unique experience.
The Exploratorium is filled with what can only be described as science experiments on an industrial scale, built to stand a hammering from the kids. Light, electricity, mind tricks, mechanical and magnetic, it’s all there. The kids absolutely loved it, as did we. My favourite part was coming across the very packed workshop where all the experiments are made, tested and QA’d. Reminded me of a machine shop I once worked in, just brilliant.