We should have known that dot-com wonderboy Mark Pincus was maturing when he sold Tribe, his social network for Burning Man attendees, to Cisco earlier this year. After a few months cavorting around Aspen and partying with movie stars, he's settled down and gotten engaged to girlfriend Alison Gelb, who works at magazine publisher Hachette Filipacchi and whom a friend describes as "a huge prize" for Pincus. As for Pincus? Not so much of a prize. Ever the romantic, Pincus gallantly waited for Gelb to recover from a momentary illness before popping the question.