A short list of the "stupid" things I did as a child:
Built a soap box car out of 2x4's, nails and lawnmower wheels and rode it down a hill and through a heavily used intersection, never had brakes on it.
BB gun wars with my friends where we would shoot each other with BB gun's.
3 wheelers....well you name it, we did it....including riding across a 6 mile RR tressel with no escape route if a train came, and jumping them off a 7ft ramp.
there are plenty more.....believe me.....and I turned out very well adjusted.
Now I look at my 12 year old, who doesnt do anything except sit ont he computer or playstation all day, and I just sigh. He will regret all this lost time when he gets older. Today's kids are overprotected and have no ambition or ingenuity. It is a shame.