Travelling in Japan recently we came across a park where the kids could start fires to roast nuts; play with real hammers, nails and saws; dig holes with proper shovels; climb on all sorts of 'unsafe' structures. Certainly the first time my 2yo had used a hammer and a saw, though she uses secateurs at home and has had a [blunt] knife for quite a while. She loved it and wants to go back.