$ ls bash: no more processes
Uh oh. Looks like someone made a fork bomb. Where I used to work, this pretty much meant that the shared server would need to be power-cycled, since even the sysadmins with root often couldn't get the problem cleaned up. Often, they couldn't even get a prompt.
I've heard a few tricks (notably, to send STOP signals rather than KILL signals, since the latter would allow the remaining threads to immediately replace the killed ones), but I've never seen a comprehensive guide entitled So, You Have Yourself a Fork Bomb?
Let's make one.