From: "Jon A. Lambert" Date: 2005-08-30T05:52:08+09:00 Subject: Adding instance methods to class at runtime I want to add instance methods to a class at runtine. $ cat testcmds.rb module Bar def hello puts "hello called" end end class Foo end Foo.include(Bar) Foo.new.hello $ ruby testcmds.rb testcmds.rb:10: private method `include' called for Foo:Class (NoMethodError) How can I do this?