29 February.

Today is February 29, 2016. It happens only once every four years. Congratulations!

Source of image:

http://www.shutterstock.com/cat.mhtml?autocomplete_id=il8h08471cjlqu10qpfl&language=fr&lang=fr&search_source=&safesearch=1&version=llv1&searchterm=29%20february&media_type=images&page=1&inline=345961592