Reusable function for scoping issues when invoking functions in JavaScript.

arrayForeach - (from Knockout Source)

var arrayForEach = function (array, action) 
{
  for (var i = 0, j = array.length; i < j; i++)
  {
    action(array[i]);
  }

};

//Usage
arrayForEach(things, function(thing)
{
  button.addEventListener("click", function() 
  {
    thing.activate();
  });
}