

I think, Venice is still the only city literally charging an entrance fee. They do that, because they got more tourists, than the city could handle. But I think what you have heard might be about tourist taxes. Many cities charge those per night. But you won’t notice it directly, it’s just that, if you’re staying in a hotel, they’ll automatically add it to the price of the room.
I second Prague. It’s beautiful and worth it whether you come for the history or the culture or the atmosphere.
Juggling. I’d find some nice stones or pinecones and teach everyone how to juggle and do some tricks. I also know an ancient game you can play with stones or knuckle bones. And I know some songs. And stories. People in the stone age had lots of free time to pass, so all of these would come in handy.