These are the natively supported easing functions, built into WebKit.
These are custom easing functions (thanks to Robert Penner & Thomas Fuchs) that can produce much more interesting transitions.
Internally the custom easing function for the transition is faked using CSS animations. Here is the code that is produced on the fly for the most recent "transition".
Morf comes bundled with the fantastic Shifty.js for tweening regular CSS properties.
If you already use Shifty heres a version of Morf without Shifty pre-bundled. Morf requires at least Shifty 0.1.3.