I remember going to the National Space Centre (there might be multiple in the UK, the one I remember was shaped like a giant white beehive) a lot as a kid. In fact, it seems to my memory that up until the age of ~14 every kids birthday was hosted there, and we never seemed to get bored of it.

Looking back on it, I find it funny that out of all the amazing things there (a full sized rocket, some kind of capsule you could actually sit in and play with the controls on), the thing that continually fascinated me the most was a little audio visualiser with a microphone, so when you spoke into it the line would deform.