$(document).ready(function(){
  $('#summary_about li:nth-child(even)').addClass('alternate');
  $('#summary_personal li:nth-child(even)').addClass('alternate');
  $('#summary_professional li:nth-child(even)').addClass('alternate');
  $('.calendar#courses ul li.entry:nth-child(odd)').addClass('alternate');
  $('.calendar#events ul li.entry:nth-child(even)').addClass('alternate');
  $('.news ul li:nth-child(even)').addClass('alternate');
});