I once whacked my forehead on a doorframe and knocked myself out. I'd just received a gift of a pair of Doc Marten's boots and put them on before going through to the kitchen. Then my phone rang and I ran back to my room (was waiting on a call about a job), forgetting that I had to duck through that doorway even when I wasn't wearing boots that added to my, already impressive, 6'4" frame.
Once I came round (about a minute later) I already had a hell of a bump and bruising (as well as mild concussion!) but no-one else was in so I tried to save face by claiming I panicked and headbutted a mugger. Despite living in a bad area in which one of my housemates was punched by a chav for no reason and my motorbike was stolen, I don't think they believed me because my reputation for being a clumsy, cack-handed, walking-disaster-area was also well known.
That and the bloodstain on the doorframe that wasn't noticed until later on.
Wardy
PS Yes I did go to hospital. Sadly they had bad news - absolutely no sense had been knocked into me in the accident.
PPS No the call wasn't about the job in end...and no...I didn't get it anyway.