There was a very short period of time (maybe a week, I think) that you could purchase macros for the Macro Library feature. For all I know, they may still be purchasable if you can call X10 and get a sales rep to find it in their system. The idea was a good one, but got dumped after a bad marketing effort tarnished the the whole thing.
We came up with a cool set of macros for gradually turning on lights that included a snooze function. I wish someone had them to publish here so you guys could see how we accomplished it. There were three macros that worked together (one called the other, which used the third one, I believe) and I think the general concept would be helpful for people trying to do more complicated things with macros.
The macro library also had special UI so that you could configure them in a Wizard format with your modules, rather than just dumping some macros in one of your rooms randomly. I don't remember what the format was for scripting the UI of the macros and packaging the library. It was a pretty cool tool. I wish we had published it for you guys and other customers to use. It would be a great way to share macros with less experienced or sophisticated users.