Lately I have been playing around with various JS Graphing libraries. In the past I have made use of Plotkit, which is based on the MochiKit libs. Overall it is a very straight forward application and easy to use.
But in wanting to make use of JQuery more and to get more up to speed with it, I came across Flot and decided to give it a whirl on the Powerball app.
For more information head on over to the Flot article.