For GitHub users;

This is  a pure-ruby  implementation of RFC4122  that I wrote  back in
2005.  I have touched its  internals a few times (mainly bugfixes).  I
know someone  has already uploaded  an old copy  of it to  GitHub, and
thats' 100% legal he has the right to do so, but I believe what I have
now is better than the older ones.  So I upload this.

It's  very  tiny  (<300 lines  ruby  code)  and  you can  simply  copy
lib/uuid.rb to your  project.  The gemspec file can  help you maintain
your dependency though.