dont know if this will work but say the dummest thing you ever did

I tripped over a fire hydrant

theres too many..

I peed my pants three times during my entire life.

All three were very stupid.

took 100 bucks to put a crazy hot sauce on my balls

it was worth it kinda, but not really.

not till like two hours later really

The dumbest thing I ever did was... enter this thread. jk
Seriously, though, I've done so many dumb things that picking one of them as the dumbest would be to disrespect the rest.

When I took the road test for my driver's license, I forgot how to start the car.

I ran into a lamppost and knocked myself out cold for an hour.

TRipping over a fire-hydrant isn't that bad really.

Dumbest thing I ever did... was probably jumping from the top-deck of a ship and completely miscalculating the lower decks...

Or the time in Belgium when I stole a warning sign: Watch out, security camera's!

Ran into a pole and cracked my forehead open. Lovely scar.

Write me thesis for my degree the weekend before it was due.

Nailed it. But still very dumb.