This little nugget was shared on some internal mailinglist, but deserves more attention. And as usual, blogging about it is a good way for myself to find it again.
To start with, install PCKeyboardHack. Follow their instructions for installation, changing the capslock key to some other keycode (getting to that in a second) and disable the default behaviour.
Now, the suggested use was as an iTerm hotkey. For that, set the keycode to 105 (F13). Then go to Preferences in iTerm, and enable the system-wide hotkey (click into the input, then press your newly assigned caps lock key, it should input F13). Here’s a screenshot showing iTerm 2 and PCKeyboardHack preferences..
I didn’t yet enable the second checkbox, just the first one to toggle to iTerm quickly, usually its already focussed the right window or tab.
Thanks to Robb for sharing it in the first place.
Other uses for the caps lock key?