Derived from online videos charting the 'Fails of the Century', Century Fail is used when a fail is just too spectacular for one year to contain it.
Today I went for ice cream with a friend of the opposite sex. My girlfriend was texting me, asking me where I was. To pacify her, I told her I was desperately trying to get away from some girl who won't stop talking - But I accidentally sent the text to said girl, as she sat next to me. She started to cry into her ice cream. Century Fail.