Mark Shuttleworth points to an excellent way to let Ubuntu Linux newbies give it a try without leaving the comfort of their Windows machines:
...I was absolutely delighted with the way Agostino Russo and Evan Dandrea steered the Windows-native installer for Ubuntu into 8.04 LTS. What I think is really classy about it is the way it uses the Windows Boot Manager sensibly to offer you the Ubuntu option. If I was a Windows user who was intrigued but nervous about Linux, this would be a really great way to get a taste of it, at low risk. Being able to install and uninstall a Linux OS as if it were a Windows app is a brilliant innovation.
Indeed. Most of the open-source software I use (I mean, besides Google and its ilk) is desktop software that runs on the proprietary Mac OS X operating system. Windows and OS X are the secret Trojan Horses of open-source software. As more and more great software is written to run on these platforms (as well as Linux, of course), a greater number of people will encounter open source and will embrace it, not because it's open source, but rather because it works.
Until the day when all software is open source, there are the many days when it's not.