Nothing that causes a flat on the road strikes me as "odd" at least when compared to those inexplicable spontaneous blowouts that happen when your bike is sitting at home hanging on the wall several hours after you last rode it. I've had those happen two or three times. Really freaky.

My kids bike had a flat. I fixed the flat, the tire went flat. I took the tire off, fixed the flat, felt around for anything that was causing the puncture but found nothing. Tire went flat. Tried two more times before I figured out that there was a wire embedded in the tire that only poked out when pressure was applied to it. Dug it out and no more problems.

Similar to Woodcraft photo, but steel spike went through the tire and the alloy Mavic rim about 30-some years ago on our custom Assenmacher tandem.
Pedal on!
Rudy/zonatandem!

I don't know how odd this is, but I'm going to say Spin Skins. Anyone remember them? They were this thin kevlar liner you put inside your tube, like Mr. Tuffy or Slime, only smaller. The issue was, if you didn't get it just perfect, it would cause pinch flats. Or, if you did line it up right, and it slid a little over time, for whatever the reason (hard cornering), you'd pinch flat. Refusing to ditch them and admitting I wasted money, I spent an inordinate effort making sure it was perfectly aligned. Only to find out a month later I flatted again, because it was shredding apart within the tire.

As far as cars go, I remember seeing my local mechanic pulling a full 1/2 open ended wrench out of a tire. How on earth the guy who ran over it hit it just right to where it was able to puncture completely through the tire I'll never know. But it sure was a sight to see.

Looked kind of like this:

^ Whoa!

Don't know if this is odd, or just my own ignorance. I hadn't ridden a bike for several years all during high school or college. When I went to grad school, I got a ten speed bike in 1972. The tire was low, so I went to a gas station and used their pump. I was not using a tire gauge and heard a loud explosion. Looked across the street to see what had happened and then realized I had over filled my tire and it was the cause of the explosion! LOL

[QUOTE=Rider51;19683370]I don't know how odd this is, but I'm going to say Spin Skins. Anyone remember them? They were this thin kevlar liner you put inside your tube, like Mr. Tuffy or Slime, only smaller. The issue was, if you didn't get it just perfect, it would cause pinch flats. Or, if you did line it up right, and it slid a little over time, for whatever the reason (hard cornering), you'd pinch flat. Refusing to ditch them and admitting I wasted money, I spent an inordinate effort making sure it was perfectly aligned. Only to find out a month later I flatted again, because it was shredding apart within the tire.

As far as cars go, I remember seeing my local mechanic pulling a full 1/2 open ended wrench out of a tire. How on earth the guy who ran over it hit it just right to where it was able to puncture completely through the tire I'll never know. But it sure was a sight to see.

Looked kind of like this:


My wife once drove over a door hinge that managed to completely go through the tire. I had no idea that was even possible, it seems like the surface area would be too great to go through the steel belting. But it happened, huge gash in the tire, wish I had taken a picture to prove it.