Kanye West seems to be fully engaged in the promotional campaign for his much anticipated fifth album Good Ass Job. Much to the surprise of his audience, 'Ye showed up at the Facebook headquarters in Palo Alto, California yesterday (July 27th). He performed four songs from his forthcoming lonplayer, including “Mama’s Boyfriend”, “Lost in the World”, “Chain Heavy”, and “Sweat on My Face”. You can check his Acapella performance after the jump.