I was upgrading a Linux kernel remotely today (don't ask), and in the reconfiguration, forgot to enable devpts. Doh! That meant that I could not spawn a shell upon login to ssh. Double doh! Now I cannot get into the machine for any more admin.
I pondered my predicament. I realized I could send blind commands to the machine, but I could not interact with it. I cracked my knuckles and went about the business of sending commands to the server and looking at the output. I figured out the problem, sent a few grep, perl, regular expression matching stuff to edit the troublesome configuration file and rebooted the box. Voila! Access!
Of course my hubris will cause great pain and suffering in the balance of the Force, but for now may I bask in my Jedi prowess.