One of the first things I do on after any new Linux install is disable the caps lock key, it is uselwss, oddly though I never map it to anything else. Here’s how to disable caps lock on Ubuntu.
Disable Caps Lock on Ubuntu 13.10
The upgrade to 13.10 actually made it a bit more difficult to disable capslock. The easiest way to do so is to install the Tweak Tool and use the settings there.
The Gnome Tweak Tool is in the standard repository, so you can install using apt-get, like so:
sudo apt-get install gnome-tweak-tool
You can then run Tweak Tool, select Typing and set Caps Lock key behavior to Caps Lock is disabled. See screen shot below.
Disable Caps Lock on Ubuntu 13.04
If you are running a previous version of Ubuntu, you don’t need to install a separate tool, but it does require a little hunting. You can find the setting for Caps Lock behavior in:
System Settings » Region and Language » Layouts » Options » Caps Lock Behaviour