Yesterday I came across "Visible Tweets" and I fell in love instantly. Apparently it was conceived as "a Twitter visualiser for rock concerts" but it is in fact a great way also to display those short messages on big screens anywhere.
If you are looking for a quick answer this is not for you, but if you actually enjoy the idea of seeing "tweets" like some kind of slow motion movie you have to try it! The fact that there is a subtle and nice design surrounding the tweets, gives them a special aura that they do not have in the web or in an api. With some music in the background it is in fact the perfect movie to display if you are giving a conference about online networking.
Here a short video of how it works:
To make things more interesting at the top of the screen you can select the special effects used to transition from tweet to tweet. Check it out for yourself: www.visibletweets.com