gistfile1.js

function add(i, j) {
    return i + j;
}

Function.prototype.continuation = function() {
    arguments[arguments.length - 1](
        this.apply(this, Array.prototype.slice.call(arguments, 0, arguments.length - 1))
    );
}

console.log(add(1, 2));
// -> 3

add.continuation(1, 2, function(x) { console.log(x); });
// -> 3

Function.prototype.continuable = function() {
    var t = this, a = arguments;
    return function(callback) {
      callback(t.apply(t, a));
    }
}

add.continuable(3, 4)(function (x) { console.log(x); });
// -> 7

Function.prototype.chainable = function() {
    var t = this, a = arguments;
    return function(self) {
        return function(callback) {
            callback(t.apply(self, a));
        }
    }
};

Array.prototype.map.chainable(function(x) { return x + 1; })([4, 3, 2])(function (x) { console.log(x); })
// -> [5, 4, 3]

Do.chain(                                                                                                                      
    Array.prototype.filter.chainable(function(x) { return x > 3 })([1, 2, 3, 4, 5]),                                           
    Array.prototype.map.chainable(function(x) { return x + 2 })                                                                
)(function(x) {                                                                                                                
    sys.debug(sys.inspect(x));                                                                                                 
});                                             
// -> [6, 7]