Winchestertonfieldville,
Iowa is a fictional
town that appears in the 2002
Adam Sandler film
Mr. Deeds (an update of
Frank Capra's Mr. Deeds Goes to Town). Minor spoilers about the movie follow, so don't read any further if you haven't seen the movie (or the TV ads...or the trailers, for that matter).
In the film, tabloid TV producer Babe Bartlett (Winona Ryder) poses as "Pam Dawson, virgin school nurse" to earn the affection of sudden billionaire Longfellow Deeds (Sandler). When asked about her background, Bartlett/Dawson stammered out a story about her birthplace "Winchester...ton...field...ville" and proceeded to tell stories about falling out of an apple tree at Boo Radley's place, breaking her arm and requiring the treatment of Dr. Pepper.
Bartlett's plan backfired, as Deeds surprised her by flying her to the actual Winchestertonfieldville (which she did not count on existing) on their third date. Deeds dragged her into the pharmacy, which the young Dawson used to frequent for malts. After an awkward encounter with the townspeople, Bartlett established her identity as "Quasimodo all growed-up," the hunchbacked relative of Bill Dawson. Deeds then located Dawson's childhood home -- built in 1996, according to the present owners. But there it was, exactly as Dawson described it: the big Victorian house with blue shutters, a big red door and a tire swing in the front yard.
For a young, upwardly mobile New Yorker who is working on a syndicated TV show, Bartlett is a surprisingly horrible liar. The moral of this story: if you're going to go undercover and do some investigative reporting, then make sure that the hometown you've supposedly invented doesn't already exist. Either that, or pick a small town that exists and claim that all the landmarks from your childhood burned down shortly after you moved away.
Then again, remember that this is an Adam Sandler movie. Just be content that he's not peeing on a wall in this one.