A friday night when you have nothing to do but be on Facebook, look at your friends pictures, and like everything and anything you see!
My fun freaky Friday plans turned into a lame, but fufilling, Facebook Friday
A Friday night when you either are too lazy to make plans or are rejected in some fashion, and waste away your time browsing facebook. Also see facebook creeper.
"Man, last friday everyone bailed out on me and I spent my night on facebook
"Yeah, facebook fridays are such a drag."