Experiences I need to book ahead for?

Hello,

Spending November in Tokyo and Osaka, any experiences or events I should think about booking ahead for? I usually keep my itinerary pretty flexible when I travel but don’t want to miss out on some unique stuff because I didn’t think ahead.
Regards,

Edit: I love museums, video games, movies, natures, animals, and science. I’m interested to hear what everyone recommends.

by 99waves