Open Source Region Stuttgart points us to a way to run (and test) Linux on your Windows PC without installing any to your computer. The "Start Linux" runs totally over the web in your browser and will even run on Firefox. Here’s the instructions from Open Source:
You can now test the Linux operating system and desktop environment. It’s as easy as ABC.
Simply click on "Start Linux". In a separate window, a complete Linux system will start on your PC, without requiring an installation. In certain web browsers, like Firefox, a small program file needs to be downloaded and run. You will be using the KDE-Desktop 3.2 desktop environment, which is equipped with the latest versions of Open Source applications, like office package Open Office, web browser Firefox, image-editing suite GIMP, and many more.
» START Linux
(The button above is only functional for versions of Windows operating system. If you wish to run the Demo Centre with another system (like MacOS or Linux), please read the FAQ section or contact email@example.com).
UPDATE: all the links are now fixed- sorry for the confusion and thanks to all those who notified me about my goof.