o.rb

[1] pry(main)> module MyModule
             |   def stuff
             |     include Module.new {
             |       def my_method
             |         puts "bar!"
             |       end  
             |     }  
             |   end  
             | end  
=> nil
[2] pry(main)> class MyClass
             |   extend MyModule
             |   stuff
             | end  
=> MyClass
[3] pry(main)> class MyClass
             |   def my_method
             |     puts "foo!"
             |     super
             |   end  
             | end  
=> nil
[4] pry(main)> MyClass.new.my_method
foo!
bar!
=> nil
[5] pry(main)>