On Saturday morning, before I left for camp, Mark noticed that my right front tire was flat. After I left, he went to have it fixed and sure enough, my tire was screwed up.
Apparently, on Friday the 13th, I ran over an inch-long screw which not only punctured the tire, but remained imbedded in it. Mark went to a tire place on Oregon Avenue, where they performed a screw-ectomy and fixed the hole in the tire. Mark just now showed me the screw that was extracted from my tire. Unfortunately, I can't put it under my pillow and get a coupon for a spare tire from the Tire Fairy or anything like that.