I'd budget some time to just stand there and enjoy the feeling of the Universe rotating around you. It's quite the experience.
Once you're done with that, I agree the Science Centre is neat. Also, they participate in the Science Centre reciprocal passes agreement, so if you have passes for another included Science Centre admission is free. I always recommend Calgarians buy Telus Spark annual passes just before you go, and then you can use at home the rest of the year. You're in the east, so maybe the Halifax one would make sense? The list of participating choices is here:
https://www.canadiansciencecentres.c...ocal-Agreement