I once put on a shirt that I had just brought in from the laundry line. My room mate thought I had gone insane when I started slapping myself and ripping the shirt off. I had a fine collection of welts all over my chest courtesy of the wasp that was in the shirt.
On the bike I have taken a few inadvertent stingers in the knees when I ran into insects. I wish they would cross at the crosswalks.