Fragments of cool code

From time to time I stumble over a piece of code, that just looks "cool". For example date literals in Ruby:

class Fixnum
  def /(part)
    [self, part]
  end
end

class Array
  def /(final_part)
    Time.mktime(final_part, self[1], self[0])
  end
end

13/11/2008 # => Thu Nov 13 00:00:00 +0100 2008

or a proper name for a throw:

catch (Exception up) {
   // log the error
   throw up;
}

The best name for a JUnit 4 test fixture (free to choose) I ever saw was in a presentation given by Peter Petrov:

@Before
public void doBeforeEachTest() {

A good name for a Ruby binding was

module Regenerated
  Inside = binding
end

eval(script, Regenerated::Inside) where the evaluation is done within the scope of another module Regenerated which acts as a namespace.