[event:Selectors](http://encytemedia.com/event-selectors/)
> event:Selectors allow you to apply an event such as mouseover, mouseout, click, et al using a CSS style syntax. It keeps your layers separated and greatly reduces the amount of code you have to write.

this is a nice set of commands to really clean up your pages, lot like the Behavior stuff for prototype.js, though currently I am fond of the adding observers via the scriptalicious stuff.