Ok I got a few to shar....
First, One time I was working on my friends new computer, everything was new and in the box it came in. So I pull out the case, and it was one of those cases where the metal bay inside is really hard to get out.. So stupid ol' me takes a screw driver and jams the thing into the metal bay, well the screw driver went through the metal and my hand sliced across the bay area removing a lot of skin and getting blood all over the place.
Second, One time I was carrying my dads SERVER with brand new stuff and I dropped it (he never found this out) right smack on my foot, it took off my toenail and left a nice bruise.
Third, One time I accidently got my finger caught in a 4800 RPM Panaflo ultra highspeed fan...Well the fan totally broke (all the blades flew off) and my finger wasnt happy either, it was crying Red, if u get what im saying.
Finally, Today I was mounting my slk-800 and the screwdriver slipped and my knuckles scraped across that heatsink edge, oh man, was that ever so painful, blood all over the motherboard, looks pretty cool though.
So those are my WW3 with my computer injuries.