Things to do with a 12yo on Sunday?

Hi all, Im visiting my niece who is 12 and lives on the outskirts of Frankfurt. I'll only have a Sunday to hang out with her, and I know what Sundays are like in Germany. Last time we were able to go bowling on Sunday, which was great, but was wondering if there was any other entertainment that would be appropriate. Was thinking of going to a movie, but I wasn't able to find any in English that were playing on Sunday of appropriate rating.

Would appreciate any suggestions. Thanks!