The Universal Access System Preferences pane is an area of OS X that is rarely visited by most users. As well as being really useful for computer users with disabilities, it also contains some of the coolest things you can do with your mac.

While the preference pane is useful for browsing through the features, all parts of it are accessible through keyboard shortcuts, which are a much quicker way of turning the features on and off.

Firstly, you can invert the display by pressing Control-Option-Command-8. This changes most windows from black writing on a white background, making your display look much more funky. Pressing the keyboard shortcut again will change your screen back to the way it was.

Secondly the zoom function can be enabled and disabled by pressing Command-Option-8. Once enabled, this allows you to press Command-Option-Dash(-) and Command Option-Equals(=, also has the + on it) to zoom in and out. These are the two keys next to the delete key, not the ones on the keypad to the right. I could see this being especially useful when giving a presentation or tutorial if you want to highlight a particular area of the screen.