Apple built a video wall out of 20 edge-to-edge 30" Cinema Displays, and on this display array they rendered 20000 application icons from the App Store, and each time someone around the world buys an application out of the App Store, its corresponding icon on the video array will light up and cause a ripple effect on the array. It's totally awesome.
You can find more images and videos at AppleInsider. Each display in the array is powered by a Mac Pro running Mac OS X 10.6 Snow Leopard, and the icons and effects are rendered using Quartz Composer.
I personally don't believe Apple's products - hardware and software - are of any magical quality that puts them above everyone else; for me, the difference lies in the sheer attention to presentation of products that you see at Apple, and this video wall is just one example of that. It not only illustrates the popularity and success of the App Store to developers attending WWDC, it also shows the power of Mac OS X, Quartz Composer, and the Cinema Display and Mac Pro.
The video array performs several functions in one go, in a way only Apple seems to be able to do. On top of that, it's just cool.