I was never really into science all that much in school.  Mostly because the experiments we did were either pretty lame or just plain didn't work.  But this one is pretty sweet!

Did you know it was possible to crush a 55 gallon steel drum by changing the temperature?  The girl in this video puts a couple inches of water in the bottom of a steel drum and then heats it up.  Then she takes that drum and puts it in a kiddie pool filled with ice.  Watch what happens.  (The first couple minutes are kind of boring but it explains the video pretty well.  Then the last 10 seconds are awesome!)