Wall Street Journal – Forget Britney Spears and Cirque du Soleil. For many gamblers, the hottest attraction in Sin City is an outdated three-reel slot machine that hasn’t produced a jackpot in nearly two decades. It is called the Lion’s Share, and in this city with no shortage of losing bets, the 20-year-old slot has attracted a legion of ever-hopeful devotees on the floor of the MGM Grand, the Strip’s second-biggest casino. The machine’s miserly track record may, paradoxically, make it the rarest of all Vegas treats: A decent bet. A generation of players has already lost money on it,…