02/29/2012 04:02 pm ET

Leap Year 2012: Best Happy Leap Day Tweets (SLIDESHOW)

Every four years, the world is given an extra day at the end of February.

For singletons, it's a day for women to propose to their men and for those with a birthday on Feb. 29, four times the celebration is in order.

Vancouver-based Peter Brouwer, co-founder of the Honor Society of Leap Year Day Babies, told the Associated Press that there are an estimated 200,000 leap year babies in the U.S. and about five million worldwide.

If you want to actually understand the science behind leap years, this intriguing YouTube video should answer most of your questions.

In celebration of Leap Year 2012, we've compiled some of the best tweets for the special day.