Custom Behaviors are based on an Broadcaster <–> Listener concept. It is very easy once you imagine it the right way! So lay back and open your mind 
Custom Behaviors are a like a Twitter stream
Yes, but what does that mean?
That means any button or timeline action can trigger a Custom Behaviors much like sending a Tweet …
But who receives the Tweet… I mean Custom Behaviour?
That’s the magic… everybody who is listening.
And how can I listen?
Well currently you … I mean Hype… can only listen at the scene and symbol level. In the scene or symbol panel you can add a new “listener”… it’s called add new behaviour
Well and what do I do then?
####You can link it to an action or Javascript. So everytime it receive a “Tweet” it fires that action.
The End
Okay a little to short but… seriously… a great tutorial on this topic would be wonderful as this concept is very powerful and would help a lot o f people.
Also check out the extension called startCustomBehaviourTicker and the example. It’s a bit more advanced and shows some of the possibilities: Extend Tumult Hype with JavaScript: hypeDocument.extensions
*Side note: Next update of Hype will allow to listen to Custom Behaviour from any function