gistfile1.rb

class Foo
  attr_accessor :blah
  
  def initialize(options={})
    options.each {|k,v| self.__send__("#{k}=", v) if self.respond_to?(k.to_sym)}
  end
end

foo = Foo.new(:blah => "test", :blargh => "stuff")

Foo can take arbitrary options and ignore things it doesn't allow. Would like to see alternative implementations.