Windows

Ruby Distributions for Windows 95/98/NT/2000
Binaries and Dynamic Link Libraries (DLLs) of Ruby and Ruby-extensions. many downloads.
http://www.ntecs.de/old-hp/s-direktnet/rb_prgs/

Ruby Entry Package for Win32
Release package, sources, Extlibs, links.
http://homepage1.nifty.com/arima/ruby/

Ruby for Windows Users
Includes easy starter kit for Windows users. Downloads: gzip, tar.
http://www.sugihara.com/ruby/