underscore-1.4.js

var array = [{name: "Foo", points: 1}, {name: "Bar", points: 3}];
var increasePoints = function (player) {
  return {name: player.name, points: player.points + 1};
};
var newArray = [];
_.each(array, function (player) { 
  newArray.push(increasePoints(player));
});
// array is undisturbed! a little clunky, though...