I'm sure most already know the reason for a leap year. As Wikipedia puts it, " A leap year is a year containing one additional day in order to keep the calendar year synchronized with the astronomical or seasonal year..... Adding an extra day to the calendar every four years compensates for the fact that a period of 365 days is shorter than a solar year by almost 6 hours.... The Gregorian calendar was designed to keep the vernal equinox on or close to March 21, so that the date of Easter (celebrated on the Sunday after the 14th day of the Moon - i.e. a full moon - that falls on or after March 21) remains correct with respect to the vernal equinox."
If I might boil that summation all down to sum it to say: It's to keep the Easter date as close to Passover every year as it should be!
Now woo... if Passover isn't a day worth Leaping, then you don't understand Passover as it's meant for you to!
It means: an act of leaping! To spring. To bound. To jump. A sudden passage or transition. A choice made in an area of ultimate concern. To spring free from or as if from the ground. To pass abruptly from one state to another.
I know that Leap Year isn't all about Passover. But today, this year, my mind reminds me of how (when you think about it) appropriately it parallels with it! :)
Leap on then! For that's a thought to bound and leap for joy over! And surely it's to be an extra day of rejoicing!