More examples of reflection / monkey-patching: String#disemvowel, Enumerable#sum class Hash def method_missing(meth,*args) if /=$/=~(meth=meth.id2name) then self[meth[0...-1]] = (args.length<2 ? args[0] : args) else self[meth] end end end x = { :name => 'Gavin', :age => 31 } x.weight = 171 x.feet = ['left','right']