Experimental macros are a way for us to test some of the new macros without having to put them through extensive and thorough review and testing. You can enable them through the Experimental library here in your Story settings page:
What's in there? Well, here's the details:
Image Map: A macro for adding a clickable image map
Random Response: A macro for choosing one response of many to display randomly.
Timed Jump: Want to force the player to make a decision? This macro will take them to another page if they don't choose within a certain time.
Thanks to Devi for suggesting these! Have a macro you'd like to see? Ask here!