In our case the school was almost completely unstructured and "play-based" was quite literal. The teachers would organize projects at "stations", but the kids w

In our case the school was almost completely unstructured and "play-based" was quite literal. The teachers would organize projects at "stations", but the kids were free to completely ignore that and go outside and play on the playground the entire time if they wanted. Of course teachers and parents played up the projects the teachers worked on, and encouraged learning through play (e.g. understanding why the sand fell the way it did or how the swings worked, etc.). But it was very indirect and light-touch. What we found was most kids naturally gravitated to things out of curiosity. Most knew the alphabet, days of the week, numbers and the like by the time they went to kindergarten. Many could even read and do simple arithmetic.