title: Meteor update template helper
body: <p>If I have setup template helpers in meteor like so:</p>
  
  <pre><code>Template.leaderboard.helpers({
    players: function() {
      return Players.find({}, { sort: { score: -1, name: 1 } });
    });
  </code></pre>
  
  <p>How can I change the subscription after an event (say a click). For example, how can I reverse the sort after a click event?</p>