Associate the ".rb" file extension with the ruby interpreter.
On Windows XP, one way to do this is to select "Tools|Folder options" in the file explorer, and to setup the association in the "File types" tab.
Another way would be to enter the following on the commandline which creates this file association for you:
assoc .rb=RubyScript
ftype RubyScript=ruby.exe %1 %*
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…