Besides the native apps we all know and love from the iTunes store, there are also web apps, which are proving more and more powerful as time goes on, thanks to better development tools.

One web app I've written is Werner Miller's Age Square: See the video tutorial for performance and method. The link to download it (so you can post it to your own web server) is available in the information box of the video tutorial.

Are there any other magic web apps out there?