//Move project thumbs when mouse over
	var timer;
	$('#thumbs_wrapper .sensor').hover(
		function(){
			var $this = $(this);
			if($this.hasClass('top') == true){
				move_projects(-0.2, 100);
				timer = setInterval('move_projects(-0.2, 100)', 100);
			}else{
				move_projects(0.2, 100);
				timer = setInterval('move_projects(0.2, 100)', 100);
			}
		}, 
		function(){
			clearInterval(timer);
		}
	);


function move_projects(n, interval){
	var current_top = getPropertyIntValue($('#thumbs').css('margin-top'));
	var indent = 205 * n;
	var new_top = current_top - indent;
	var max_top = get_max_top();

	if(typeof interval == 'undefined'){
		interval = duration;
	}

	if(new_top > 0) new_top = 0;

	if(n > 0){//up
		if(current_top > max_top){
			$('#thumbs').animate({"margin-top": new_top + 'px'}, interval);
		}
	}else if(n < 0){//down
		if(current_top < 0){
			$('#thumbs').animate({"margin-top": new_top + 'px'}, interval);
		}
	}
}

setTimeout() and setInterval():

http://www.elated.com/articles/javascript-timers-with-settimeout-and-setinterval/