Cagatay Civici has posted an example of how to quickly create a JSF slider component, built off of the scriptaculous slider widget. I like this for a few reasons:

1. It shows off an excellent use of the composition component functionality available in Facelets.

2. It shows how easy it is to create cool components using JSF - this one could be done in only a few minutes.

Also, you can see how this component may have progressed: First as a block of HTML on the JSF page, and then likely refactored into a composition component. This is how JSF component development should proceed, in my opinion - not by creating a bunch of components at the beginning of a project, but rather by refactoring existing code into a component as needed.