Twitter Real Time Search
If you are using Twitter regularly you might find the Twitter real time search script handy. Tweet Scan makes it possible to search in real time for keywords on Twitter. The result of the search is displayed on a individual page that can be bookmarked or subscribed in your favorite RSS reader. If you would for instance want to stay updated on anything related to Yahoo you could search for Yahoo and add the RSS feed to your reader.
Flitter a Flickr Twitter realtime screensaver
If you are looking for a rather unique screensaver for Windows 2000, XP or Windows Vista you should take a look at Flitter which is a mashup from Flickr and Twitter at the moment. What it does is that it is retrieving realtime data from both Flickr and Twitter to display those when the screensaver is active.
You obviously need a computer that is connected to the Internet to use this screensaver but it is very well worth it. The default setting for the screensaver pulls data from the public timelines of both Flickr and Twitter but you have the possibility to custom this further.