I definently have a few.
The embarassing one:
I was at the track trying to figure out why our car had no power steering. Turns out the foam in the power steering container clogged the lines/pump. So i take it all apart and run the air compresser through all the lines to get them all cleared out. Then i did the same to the pump not realizing that the other hole the air would come out of was pointed right at my face and blam. Nice big face full of power steering. The team next to me was laughing sooo hard.
The omg that really hurt:
Friend has a veilside body kit on his rx8 so i couldnt lift it with my jack. So i made a little spacer out of 2x4 wood so i wouodnt hurt his kit. And as i was lifting the car i was feeling to make sure the wood was where it needed to be. Then the wood decided to split in half pinning my fingers between the car and the jack. Didnt feel to good at all.
As much of a pain the outback is to work on with the rust, i havent really done anything dumb with it yet. Sooner or later though it will.