GMaps.js allows to define map events very easily:
map = new GMaps({
  el: '#map',
  zoom: 16,
  lat: -12.043333,
  lng: -77.028333,
  click: function(e){
    alert('click');
  },
  dragend: function(e){
    alert('dragend');
  }
});
      Note: You can check the list of map events here.