In a rare move, the largest sports arena in Columbus, Ohio, relaxed a key policy for an event in April, allowing attendees to freely exit and reenter a game in progress. Nationwide Arena simply couldn't expect fans to stay seated for nine hours of action. It's among the accommodations event spaces across the country are making in bids to capitalize on the rise of arena-packing video-game contests, which they hope will attract a new generation of event-goers -- and with them increased ticket and concession sales. For owners, operators and concessionaires of venues, e-sports are the biggest new mass-spectator events since raves, the Ultimate Fighting Championship and the X Games. An estimated 47 million North Americans will tune into e-sports this year, according to research firm Newzoo.