We made a good decision last weekend. We attended Žabarije, a local children event with numerous creative corners, games, face painting, music for children, a clown, a magician and, what seemed to be by far the most attractive activity for our two-year old were boxes with natural materials - presenting corn, wheat grain and hay to city kids :)
Oh, and observing and touching frogs and snails, off course.
I'm sure I'll copy the idea of putting various materials in boxes for the toddler to touch and explore. So many additional options... So far, we've only occasionally offered him a rice box in our apartment during the winter - with lots of stepping on lost rice grains everywhere in our apartment - but you get used to that, don't worry ;)