College @ Home lists 50 ways to use Google Chart API, a simple API for dynamically generating charts. Plot functions, visualize the evolution of the number of subscribers to a FeedBurner feed, display the results of a poll, transform HTML tables into charts and much more. Of course, you can also use Google's charts just for fun.
If you only need to create a few charts, generators like Chart Maker, Google Chart Creator, Chartpart let you create charts without reading the documentation. To use Google Charts programmatically, check this list of wrappers for Java, C#, PHP, Python.{ Thanks, Fiona. }