So, it’s a Citi Field first today: The Mets will play their first doubleheader at the new digs, starting in about ten minutes. (They played one doubleheader last season, losing twice in Philadelphia.) No other sport provides you the opportunity, however rare, to enjoy the product twice at the same price you usually pay to enjoy it once. We love doubleheaders. Anyway, in game one, Johan Santana takes the mound against the Dodgers’ Hideki Kuroda, which will hopefully go quickly, because the nightcap pits Oliver Perez against knuckle-baller Charlie Haeger, and it’s very likely that game will last seven hours. By the way: If the Mets sweep this, and the Phillies lose at San Francisco late tonight, there will be one team in the city in first place, and it won’t be the Yankees.