Folks should read the fascinating document which is the LEGAL file which comes with the Ruby source code. http://www.ruby-lang.org/cgi-bin/cvsweb.cgi/ruby/LEGAL?rev=1.12.2.2;content-type=text%2Fplain
The Ruby source contains not one, not two, but SIXTEEN different licences including the "Beer-Ware" license. Do YOU want to be the person who has to figure out if their company can modify and/or ship Ruby? Or if the seventeenth license is compatible with the previous sixteenth? Welcome to licensing hell. This is the end of the road down which accepting multiple licenses into your project gets you. This is a road Perl 5 has strived to get itself off and Perl 6 has avoided taking altogether.
