Ew. No idea what I did, but all of a sudden, I couldn't log into one of my Ubuntu (10.04 LTS) boxes.

After a long look, I found the solution somewhere between here and here:

  1. Reboot the jerk.
  2. Hold shift to get your Grub menu.
  3. Find the kernel line (see link) and add - to the end of that line: init=/bin/bash rw
  4. Hit ctrl-x to boot.

When you get in:

  1. mount -rw -o remount /
  2. pwconv

Then reset the password on one of your admin users by passwd username and you're golden. Just reboot and everything should work again. I hope. :)