Having only recently discovered SIMILE and Exhibit (thx Armand), I have had the chance to dig a bit deeper for one of my recent projects. The framework is extensive and allows for many types of visualizations. Moreover, you can easily convert your existing data using Babel [6], or search the existing wiki [7] for information on how to use it to connect for example to SharePoint lists [8] or even to Twitter [9].
So check it out at: http://simile-widgets.org/ [10]
Links:
[1] http://pulse.veltsos.com/category/it/software/development
[2] http://pulse.veltsos.com/category/it/open-source-foss
[3] http://pulse.veltsos.com/category/it/visualization
[4] http://pulse.veltsos.com/category/it/web
[5] http://linux.philosweb.com/drupal/system/files/image_2_123.png
[6] http://simile.mit.edu/babel/
[7] http://simile-widgets.org/wiki/Main_Page
[8] http://code.google.com/p/simile-widgets/wiki/Timeline_SharePointLists
[9] http://elijahmanor.com/webdevdotnet/post/Visualize-Your-Twitter-Timeline-With-jQuery-And-Simile.aspx
[10] http://simile-widgets.org/