Designer, meet plugins
We've already talked about how programmers solve the same problems over and over again. It's these common tasks that jQuery simplifies so that we can accomplish these tasks with a minimum amount of code. What about the tasks that are only somewhat common, like the ability to customize the appearance of tooltips?
That's where the jQuery community becomes important. Developers in the jQuery community write code that extends the functionality of jQuery to simplify tasks that are only somewhat common. These bits of code are called plugins, and they are used in conjunction with the jQuery library to make coding complex interactions, widgets, and effects as simple as using the features already built into jQuery.
You'll find a library of hundreds of jQuery plugins on the official jQuery site at http://plugins.jquery.com. In addition to this, there are literally thousands more available from sites across the Web for just about any task you want to accomplish...