Moms have Mother's Day, dads have Father's Day, and couples have anniversaries. But this weekend, good pals have Friendship Day. It's the perfect chance to spend some QT with your BFF. Here are 20 ways, inspired by Instagram, to celebrate the bond you have with your best girlfriends. You could go beer tasting, make friendship bracelets, or opt for an old-fashioned slumber party. See those ideas and more!