Live CD - Try Linux Without Installing Anything

Is this possible? Now it is. You can run applications, like browsers, word processors, even a whole operation system (OS) from a CD. Or a USB flash drive.

Live CD is a OS or programs that run from a CD. Give it a try. Several major storage companies are working on it. Even Microsoft are wondering how to speed up the slow growth of their MS Office, that's why they bought Groove, trying to create a virtual online office.

References:
The LiveCD List
If you're not brave enough to switch to Linux, there is an alternative - Live CD - Guardian Online