I have to say that even if you're not stupid to start with, you soon will be after a few 'games' like helmet boxing

. Acceleration trauma is not kind to neural connections.
Yes, we did daft things as kids too but I can't think of anything as barm-pot as that. I've been guilty myself of jumping out of trees from as high as you dare, sword-fighting with braches, sledging down wooded slopes on dustbin lids et al but volunteering to be punched in the head ... er ... let me think ...
One aside,
jks, how long ago was it that you were playing around smashing flourescent tubes? You do know what's inside them and the good reasons to avoid these substances? Still, if it was a long time ago and you've not seen any ill-effects then you probably got away with it :fingers crossed:. Then again, given what chemistry class used to be like when I was at school, your exposure was probably minimal compared to mine {we used to play with liquid mercury and mess around with radiation sources as well as drop chunks of sodium down the drains

}.