Question

Where is the shortest way?

var height=0;
$('.el').each(function(){
height<$(this).height()?height=$(this).height():height=height
}).height(height);

If it exists, of course.

EDIT:
Nice, thanks gyus!

var h=0;
$('.el').each(function(){
    h=Math.max(h,$(this).height());
}).height(h);

Answer 1

Slightly shorter, but cleaner and faster I guess:

$(".el").height(Math.max.apply(null, $(".el").map(function () {
    return $(this).height();
}).get()));