In researching some development platforms (PHP, Groovy, Grails, etc..) I stumbled on a Grails testimonial page. Since we also want to integrate PHP with mySQL, Grails looks very useful.
After reading a few testimonials at : http://grails.org/Testimonials I started clicking around and found a very nice little twitter app. It allows the real time display of photos as they pass through twitter.
It's like watching 100 new cell phone pictures every 20 seconds, from all over the world, with all sorts of content. The UI is clean, the app is fun, and it's interesting to watch snapshots of time across the world.