It is delightful to see Watir gaining popular, attracting more attention outside Ruby world. From many of those testers/developers, tasks such as "downloading Ruby one click installer", "gem install", and "proxy setting behind firewall" might just be too much. One simple solution is using PRoR.
I packaged a Ruby distribution named as PRoR (Portal Ruby on Rails) based on Ruby one click installer back in 2007, its origin purpose was to create a Ruby distribution running a web application (Ruby on Rails, of course) on a thumb drive. Yes, it worked and impressed a few people. Then I discovered Watir, so naturally extended it to include Watir and supported libraries.
The advantages of using PRoR are
- Small and compact, only around 8Mb
- Easy to to install (double click setup.exe, click 'Next', 'Next', then done)
- Well tested, you don't need to worry about gem compatiablities
- Rails included, you might find it useful for your testing purposes