Today at work, Pete discovered an exploded frozen soda in the fridge:
The can in the photo is the same orientation it was in the fridge: the soda has blossomed up and out of the can, then immediately frozen in place. The sudden drop in pressure as the contents burst out of the can must have frozen the soda nearly instantaneously.
Here's another description of the same phenomenon. There's no photo, but it includes a very realistic description of how a soda can could be neglected in the freezer in the first place: "Ooh, something shiny on the Web!"
While reading about the relationship between pressure and temperature, I found the frightfully informational Phase diagram of water. It turns out ice can form in a number of different ways, depending on the pressure and temperature. I was amazed to see that there really is a substance called ice 9, just like in Vonnegut's Cat's Cradle, though I hope it doesn't end up like his did (the whole world froze).