I've got two! 
First of all, I was installing an AutoMeter oil pressure gauge in my Duster. I was torquing the adapter into the hole, and apparently there was a defect in the adapter. The hex head broke off, leaving the "hollow bolt" stuck in the cylinder head. And that car was my daily driver at the time...
My second story is changing the cone air filter on the turbocharger. I installed that air filter when the motor was out of the car during the engine swap. The screw on the ring gear was facing the rear of the motor, where I could absolutely NOT get to it when the motor was in. So I had to use a BFH and a long screw driver to break the ring gear clamp and rip the original air filter in two in order to get it out!