For the Mix10K smart coding challenge, I've create an application runtime that hosts, manages and runs cloud-based applications. The runtime is called Cloud Light, and per the rules of the Mix10K challenge the code and visuals weighs-in less than 10KB. The runtime environment also features an online application store from which you can download and install applications.
View the Cloud Light in the Mix 10K gallery and please vote for it.
Runtime Overview
- Provides basic window management capabilities like opening, closing, activating, minimizing and restoring of windows
- Allows you to install applications directly from the web
- Installed applications information is persistent, with the applications themselves downloaded when the runtime starts
- Allows you to uninstall applications with a single click
- You can also install Cloud Light as a Silverlight Out-of-Browser Application (right click and choose "Install Cloud Light.." from the context menu)
Title Bar Overview
The Title Bar shows the active application's title and also show the current date-time. Additionally, it features four buttons on the top-right corner that enable full-screen toggling, showing/hiding of the application store, minimizing of the active application and closing of the active application.
Applications Store Overview
The online Application Store lists all currently available application in the Cloud. To install any application just click on the entry title, and the application is downloaded and installed - once installed, it should appear in the Application Bar. Going further, more applications will be available through the store.

Application Bar Overview
The Application Bar hosts all the currently installed applications, each application getting an icon for itself. The icon also with a highlight represents a running application, and each application can only have one instance running at a go. A single click to an application icon starts the application, if already running it activates it, if previously activated it minimizes it, and if minimized it maximizes and activates it - really simple, right. Also if an application is open, Shift+Clicking the icon closes it and by Ctrl+Shift+Clicking on the icon you can uninstall the application.

Extensibility
Apart from the limited applications selection available in the Application Store, you can also create your own applications and install them using the Console application. In a separate post I will detail how you can create your own custom applications and install them.

Another simple point of customization is setting the wallpapers, again through the console - so something like "setwallpaper -url:http://adsoftheworld.net/download/windows7/winwall7057_23large.jpg" will change the background into:

And in addition to the built-in Commands, you can also create custom Console-based Script Commands, and have them automatically register with and be availed through the Console Application (see Silverlight Console).
Summary
So for 10KB worth of c# code and xaml, I think we have a surprising functional runtime that is both extensible and light thanks to Silverlight. It in some-ways can be seen as a prototype for a managed Cloud OS that relies on the Cloud but provides applications in the form we know them today. And in terms of the design it speaks to the simplicity and discoverability that iPhone brought, something that I think needs to be embraced in desktop-applications' designs.
View the Cloud Light in the Mix 10K gallery here
and please vote for it if you like it.
Acknowledgements
Default Grass Wallpaper by Radoslaw Rokita [vathanx@live.com]
Application Icons by Judge