Custom CCK fields

CCK is the future for site designers, but how do we make fields do what we want them to? I mean, its no good to have an input field without validation and formatting options, is it? Forthurmore, how does this stuff 'magically' show up in Views?

Never fear, its all there, and we can go through it all step by step.

The current lesson plan is:

* Detail a Content Construction Kit field.
* Build a CCK money field module (for various currencies). Maybe even a form that shows when the user is viewing the node, and lets the user choose a currency.
* Add Google Video functionality to a YouTube CCK field to demonstrate extensibility.