Fever Pitch

When relaxed and charming Ben Wrightman (Jimmy Fallon) meets workaholic Lindsey Meeks (Drew Barrymore) she finds him sweet and charming, they hit it off and when it is winter Ben can spend every waking hour with Lindsey, but when summer comes around the corner Lindsey discovers Ben's obsession with the Boston Red Sox. She thinks it is perfect until everything goes downhill for them, based on Nick Hornby's novel "Fever Pitch"

Fever Pitch, which was released as The Perfect Catch outside of the United States and Canada, is a Farrelly brothers romantic comedy film. It is a remake of a 1997 British film of the same name. Both films are loosely based on the Nick Hornby book of the same name, a best-selling memoir in the UK. Hornby also wrote the screenplay for the original film, but had no input for the American remake. While both the book and the original 1997 film are about Football (soccer), this version, aimed at the US market, is about baseball. The film opened in theaters on April 8, 2005.

Source: Wikipedia