Force kernel penic on linux?

Hey there!
I want to force a kernel panic, but don't really know an effective way to do it.
Tried feeding zeros to the memory by "cat /dev/zero > /dev/mem", but it has non-device access disabled. Tried killing init in various ways, but it ignores all those kill calls or something, so nothing happens. Making the system divide by zero shoul do the trick, but i don't know a fairly easy way to do that.
Any ideas?

Does init ignore kill -9? That should be very much impossible.