Galentine's Day is a somewhat fictional holiday (at least it used to be) that is celebrated on February 13, the day before that other made-up holiday (cough, cough, Valentine's Day). It's a day for celebrating the love you have for your lady friends, whether they're single or not.
The holiday started as a fictional holiday created by Leslie Knope in a 2010 episode of Parks and Recreation, as a way to do something often overlooked in American culture, which is to celebrate the joys of female friendship.
As Leslie explained it: “Every February 13, my ladyfriends and I leave our husbands and our boyfriends at home, and we just come and kick it, breakfast-style. Ladies celebrating ladies. It’s like Lilith Fair, minus the angst. Plus frittatas.”
The festival falls each year on February 13th: Valentine's Day-eve.