If you've ever done something really dense and laughed at yourself later, you owe it to yourself to go to NPR's This American Life and listen to a recent edition called "It seemed like a good idea at the time...". It features a series of people telling their 'dumbest ever' story.
It opens with a police officer telling the story of the time he crawled in the back of his car for a late night nap, only to wake up and discover he'd locked himself in the back of his patrol car....
The guy panics for 25 minutes then realizes he has a cell phone with him...but he's not sure where he's at...so he call's 911, who mistakenly reports it as "Officer Down", bringing out everything from the dog catcher to the cavalry.
Just go ahead and listen here