Things I did as a kid that kids probably don't do now because they might be dangerous:
Riding a bike without a helmet and riding for miles. Drinking from the hose. Going sledding down a steep hill that ended onto a busy street. Was tricky to stop in time, but we managed it. Walking home from a friends alone at late at night. Staying outside until dark, playing with the neighborhood kids. Climbing a mountain just outside of town by myself. Mom gave me a paper bag lunch, told me to eat it when the sun was directly overhead and then immediately come back home. I never made it to the top of that mountain, but I met a lot of sheep and picked lots of buttercups to take home to share with my brother and sisters to see if they liked butter. Visiting Farmer Brown's barn when the baby lambs were born and getting to pick them up and hug them. Walking on Railroad tracks to the river and back. (there was only one train using the track and it ran at 5 pm.) Putting pennies on the track so the train would flatten them.