Miso is an open source toolkit designed to expedite the creation of high-quality interactive storytelling and data visualisation content.

Great selection of visualization tools.

Rickshaw is a JavaScript toolkit for creating interactive time series graphs.

D3 allows you to bind arbitrary data to a Document Object Model (DOM), and then apply data-driven transformations to the document. As a trivial example, you can use D3 to generate a basic HTML table from an array of numbers. Or, use the same data to create an interactive SVG bar chart with smooth transitions and interaction.

Create Interactive Data Visualizations for the Web