Ok here's mine.
I had a NIKKO buggy that I got from my first trip to Singapore, and that thing was FAST.. so after going over everything (including my dog's legs when they were asleep and really irritating the crap outa them) I got bored.
So, I put on the sprinkler's on the lawn.. and once it was pretty soaked, I let the buggy rip all over the lawn, much to the disgust of my parents.. but then what did I know back then.. not to say I know any better now

!
Was having a BLAST with the buggy, until I went thru a slightly large puddle and water went into the chassis and SHORTED out the entire electronic controller.
So, opened up the puppy saw wires and stuff going all over the place, ( was about 11 at the time and didnt know my A from my E about circuits or electronics) poked and prodded around.. thought I solved the problem, connected the battery.. switched it on and POOF.. went up in smoke.LOL!
Miss that old buggy.. for the sole and simple reason that it used to drive my dogs NUTS!!