A recent editorial in the NYT informed me about the federal government's new resource - As noted in the editorial, the site is still new and does not provide yet any direct data visualization and manipulation widgets, although sometimes there are links to other sites where such widgets are available. Still, this “one-stop shop for free access to data generated across all federal agencies.” as Peter Orszag describes it, promises information architects and user experience designers an unparalleled opportunity to experiment and develop new paradigms of data visualizations. For the most part, access to very large sets of data is not readily available, or so easily found.
Below is the search result for the term 'flu.

The link to the CDC's library of widgets shows a surprising wealth of them readily available for consumption. Embeded in this post is the CDC's FluIQ widget, as a useful example...Check it out: