Dealing with an odd-sized year (365.024219 days) is not as easy as you think. Not only do we have the popular Gregorian Calendar (4-year cycles, with “by-years”), but some geek gurus have proposed the Earthian Calendar (33-year! cycles). There’s even a connection to Stonehenge.
Update (3 March). A careful look at the Earthian Calendar site reveals a calendar generator! This year’s calendar reveals the 2012 leap day as 11 Pisces 0004 Earthian (or Copernican, as the author prefers to call it).