text: function whenTouchingAny(sprite, group, event) {
    var g = group();
    function f(s) { 
      collisionEvents.push(
        {a: sprite, 
         b: function() { return s; }, 
         event: event});
    }
    for (var i=0;i<g.length;i++) {
      var gg = g[i];
  	f(gg);
    }
  }