An Olympiad is a measure of time used in Ancient Greece to signify a four year period each of which begins in the year of the Summer Olympic Games. By this measure and only counting the Modern Olympic period beginning in 1896 the 29th Olympiad began in 2008.
2009 will be 29,2
2010 will be 29,3
2011 will be 29,4
2012 will be the 30th Olympiad
Using the 776 BC date of the Ancient Olympics as the starting point: 2008 is the 696,4 Olympiad
Olympism is is the values of the Olympic games. For more information see related link below