This Easter Egg, which is called "Rocket Launcher", is a little bit trickier to find than NyanDroid. For this one, you'll need to install LauncherPro (one of the better launcher replacements anyway), which will let you access Activity Shortcuts. When placing the Activity Shortcut, just choose the Rocket Launcher option from the menu, and when you open that shortcut it will put you into the Rocket Launcher. As we said, it's essentially flying through space with app icons whizzing by you. If you tap the screen, the icons will slow down and allow you to tap an icon to launch the application.
We're not saying it's very useful, but it is marginally more useful than NyanDroid. The maker of the video claims it is an example of "Dreams" in ICS, which are essentially interactive screen savers. Not sure why you need a screen saver, but necessity shouldn't get in the way of a little fun, right?