Just found this:
http://www.youtube.com/watch?v=o8nCg0n0zXM&mode=related&search=
Care for comments?
PS: Same with explanations at:
http://www.metacafe.com/watch/55826/who_can_explain_this/
how it the problem ?
that is al litte block of graphite.
if this is deep frozen (by expanding liquid gazes)
this "antimagnetic" unnormally "show" is this effect.
Pese