It's a corker
You might have seen this video doing the rounds on facebook. It's a way to get the cork out of a wine bottle without a corkscrew by putting it in your shoe and hitting it against a wall. I haven't tried it but it seems believable so i thought I'd try to work out whats going on. The strange thing is that it seems the wrong way round. As the bottle hits the wall the wine will create a large force on the bottom of the bottle not the top. I tried simulating it in Algodoo and could see the water swishing about but the biggest force seemed to be on the bottom not the top. After a while I gave up and googled the answer. I found it on the naked scientist website. What seems to be happening is that as the wine rushes forwards air pockets form under the cork (cavitation), when these bubbles pop the wine rushes back up the neck of the bottle hitting the cork out.