Ulteo has squeezed the entire OpenOffice suite online, which allows you to bring along your favorite open source office programs together with you, even if you don't possess a thumbdrive.
According to Ulteo, all you'll need is
a modern web-browser with Javascript and the Sun Java Runtime 1.4+ Environment plugin enabled. It's been successfully tested on Firefox 1.5+, IE6/IE7, and Safari.
Ulteo's online OpenOffice provides a fairly generous 1GB of free storage upon registration of an account, comes with support for PDF output and the OpenDocument Format as well as collaboration features. Unfortunately, their OpenOffice servers are currently overwhelmed by enthusiastic users, so you can only register for an account and wait for the traffic to ease off.
For a quick preview of what it's like, check out Hands on with the new online version of OpenOffice.org @ Ars Technica. Strangely, the Ars writer could not find any of the collaboration features that Ulteo claimed their online OpenOfice would have. Like the Ars guy, I'm gonna attribute this omission to its beta status.