add(1)()(3)(8).valueOf();

add(3)(5)....valueOf().js

function add() {
	var slice = Array.prototype.slice, t = 0;
	function add2(k) {
		k = slice.call(arguments);
		for(var j in k)
			t += k[j];
		return add2;
	}
	add2.valueOf = function(){return t};
	return add2.apply(null, slice.call(arguments));
}

function add(){function a(b){b=d.call(arguments);for(var e in b)c+=b[e];return a}var d=Array.prototype.slice,c=0;a.valueOf=function(){return c};return a.apply(null,d.call(arguments))};

console.log(+add(1,2)(3,4)(5,6,7)()(8)); //36
console.log(+add(3)(5)); //8
console.log(+add(4)()(6)); //10
console.log(+add(8)()(9)); //17

// http://www.quora.com/Can-anyone-write-a-Javascript-function-that-does-this-add-1-2-8-should-return-11-i-e-the-sum-of-the-arguments-given-number-of-arguments-can-be-any-natural-number
// https://www.linkedin.com/groups/Can-anyone-write-Javascript-function-121615.S.5962319091699113985