This is a bit of a strange one. I'm running Ubuntu 12.04. It's been working well but today, I ran into a hell of strange phenomenon. I can no longer type a lower-case 'c' in bash. At first I thought it was a misconfiguration for the gnome terminal but I tried both a stock xterm and directly at the console (ctrl+alt+F1) and the issue was the same.
I can type an upper-case C without any difficulty and I can type lower-case 'c' in any other terminal based program (vim, bash, less, etc.). The lower 'c' also works if I jump into plain old sh.
I looked at all the configuration files I know of and haven't found anything incriminating in there. I suspect it's not going to be that simple anyway because if I run bash with the '--norc' option from within sh, the problem remains.
I don't know what else to check. In fact, if I wanted to cause this problem on a given machine, I have no idea how it could be done. Total mystery.