My second session at WordCamp NYC was with Richard Dinh. Richard works with Northpoint Solutions in NYC.
When he was learning WordPress, he found himself having to go back to the same things over and over again. Remembering where to find a code snippet for this or that was becoming a pain. So he put together a bunch of sample plug-ins that he could go back to whenever he needed to remember how a certain bit of WordPress functionality works.
The result is a little code repository on Github of sample plugins.
You wouldn’t want to use these “as is” in any project you’re doing. He’s clear about saying these aren’t for use on production installations. But if you want to know how to construct a custom post type and display it, this is a handy little spot to look.