A very simple countdown Timer ( Modified from http://jsfiddle.net/dpeaep/LQGE2/1/ )

inkmonkCountdown.js

angular.module( 'inkmonk.directives', [] )
.directive('inkmonkCountdown',['$compile', function($compile){
    return {
	    restrict: 'AE',
	    template:  "{{counter}}", 
	    scope:  {
	        counterStart : "=start",
	        dependsOn: "=runduring"
	    },
	    controller: ['$scope', '$element', '$attrs', '$timeout', function ($scope, $element, $attrs, $timeout) {
	    	$scope.counter = parseInt($scope.counterStart);
	    	var stopTimeoutRecursion = false;
		    $scope.onTimeout = function(){
		        $scope.counter--;
		        if ($scope.counter > 0 && !stopTimeoutRecursion) {
		            $timeout($scope.onTimeout,1000);
		        }
		    }
		    $scope.$watch('dependsOn', function(newValue, oldValue){
		    	if(newValue){
		    		stopTimeoutRecursion = false
		    		$timeout($scope.onTimeout,1000);
		    	}
		    	else{
		    		$scope.counter = $scope.counterStart;
		    		stopTimeoutRecursion = true;
		    	}
		    });
	    }]
    }

}]);

Example Usage:

<div ng-show="waitingForColors">
  <div inkmonk-countdown  start="60" runduring="waitingForColors"></div> seconds left
</div>