Photosynth smartly and automatically stitches together user photos to create an explorable 3-D environment. It gets better as more photos come in. See also the map of other synths from the inauguration.
The New York Times published a great interactive piece a few days ago allowing readers to explore the salient and new terms in all past U.S. inaugural speeches.
For a similar visualization of a much nerdier domain, check out my yummy tag timeline.