I have a tie for the dumbest thing i've done.
the first thing that i did was ride on the hood of my mom's car as she dorve down the street and then she suddenly stopped and i flew off. nearly twisted my knee.
the second thing would be when i jumped out of my dad's truck while he was driving. i did it cuz i saw the commercial when the boy was telling the grandmother to "tuck and roll" as he shoved her out of the car. Oh and this isnt an ordinary truck it is one that vendors use. If u knw anything it is like a UPS truck.