So are lunar cycles:
Monday, October 17, 2005 Full Moon
Wednesday, November 2, 2005 New Moon
Wednesday, November 16, 2005 Full Moon
Thursday, December 1, 2005 New Moon
Thursday, December 15, 2005 Full Moon
Saturday, January 14, 2006 Full Moon
Sunday, January 29, 2006 New Moon
Monday, February 13, 2006 Full Moon
Tuesday, February 28, 2006 New Moon
Tuesday, March 14, 2006 Full Moon
Wednesday, March 29, 2006 New Moon
Thursday, April 13, 2006 Full Moon
Thursday, April 27, 2006 New Moon
Saturday, May 13, 2006 Full Moon
Saturday, May 27, 2006 New Moon
Sunday, June 11, 2006 Full Moon
Sunday, June 25, 2006 New Moon
Tuesday, June 11, 2006 Full Moon
Tuesday, June 25, 2006 New Moon
Wednesday, August 9, 2006 Full Moon
Wednesday, August 23, 2006 New Moon
Thursday, September 7, 2006 Full Moon
Friday, September 22, 2006 New Moon
Saturday, October 7, 2006 Full Moon
Sunday, October 22, 2006 New Moon
Sunday, November 5, 2006 Full Moon
Monday, November 20, 2006 New Moon
Tuesday, December 5, 2006 Full Moon
Wednesday, December 20, 2006 New Moon
Indeed.