The New York Times has produced an interactive transcript visualizer that allows exploration of the transcript for the recent Democratic debate in the US. It shows word count by speaker with a simple bar graph and illustrates the size of the various speech segments with a multi-strip rectangular region. It also supports highlighting a search term within the transcript. The tool doesn't do a great job of showing who spoke when. I would also like to see the capability of highlighting multiple search strings in the display. On the whole, I think it is quite well done.
[Link discovered via the open house project]