I had two stupid ones.
The first one: I was up on a stepladder, using a Leatherman Micra to cut open a cardboard box on a shelf. (Sounds dumb already, right?)
I sliced down the side of the box, then used my other hand to rip the front face open... of course, I slipped or something, and impaled the fleshy part below my thumb on the still open knife blade. Only four stitches, but it was deep, and it throbbed.
The second one: my wife and a couple of our friends are a couple of miles out on a hike. We sit down to eat. We have an avocado; I have my brand new and astonishingly sharp Delica 4. I slice around the avocado. I pull it in half. I use the typical "tap and twist" technique to remove the pit... except the Delica slices straight through the pit, splitting it nearly in two, and slices a beautiful arc into the base of my index finger.
"Oh good", I said. "I can see a blood vessel". No permanent damage, and I only needed steri-strips to seal it up, but I do still have the scar. The fun part was hiking back with my arm held above my head, with my torn shirt to stop the bleeding. Apparently I looked like I'd been attacked by a bear, because I was also limping from a particularly exhausting soccer game the day before...
Come to think of it, I had a 20 minute drive holding my hand above my head for the first one, too... heh!