Taking bets on the age of Joan Rivers can be a lucrative business. Real-estate guru Barbara Corcoran hit the jackpot while lunching with 12 female friends at Doubles as the surgically ageless comic sat at a nearby table. A source reports, “Barbara suggested the women all have a pool for $10 each to guess Joan’s age. Barbara went over to her table to say hello, and subtly asked her age. The women didn’t believe that anyone would have the nerve to ask Joan such a question, so they accepted Barb’s guess of 77. Barb won $120 and offered Joan, who was in on the joke the whole time, half. She told Barb to give it to charity.”