I broke my finger once. Someone had lifted the top weight plate on the weight stack and then put the pin back in, so the first plate was elevated, if you see what I mean? Then dumbass me comes over, puts one hand on the weight stack, pulls out the pin, and bam, the top plate comes down on my fingers!

Not the most 'hardcore' injury, I know.
I've got stuck under the bar a couple of times when benching and had to literally roll the bar down my torso til I could sit up and lift it off!