$('contribThumbs').getElements('div.userContribContainer').each(function(t){
    //mouseover add class for hover state
    t.onmouseover = function(){
        t.addClass('studentListHover');
    };
    
    //mouseout remove class for hover state
    t.onmouseout = function(){
        t.removeClass('studentListHover');
    };        
});