Just discovered this amazing tool which I saw for the first time on the BBC's coverage of election night when their presenters were reviewing what was being written/said in the blogosphere (and tweetosphere).
It takes text from a number of sources (upload a word document, RSS feed, web URL etc) and converts it into a 'word cloud'. The words which appear most often in the text are the largest in the cloud.
More impact than a Powerpoint presentation, I think.
To try it out for yourself, just click on this link: www.wordle.net