The Simply Physics site collects images of things that flew at and into MRI machines, attracted magnetically:
DANGER! Flying Objects!
Once you’ve been in the MRI field for any length of time, you start hearing all of the various horror stories about thing that have flown into a scanner. Often, newcomers don’t take the real danger of flying objects seriously until they witness an oxygen tank or gurney flying into a magnet themselves. This page will contain a collection of pictures and stories of metalic projectiles. Please show this page to all MRI newcomers, for their own safety and the safety of their patients!
[via Ivan Oransky]