Okay, bear with me for a minute: This is a film about a real novel, The Life and Opinions of Tristram Shandy, Gentleman—a 700-plus page behemoth written in the late 1700s.
Seriously, pay attention: The novel—dubbed the first post-modern novel—is a bawdy English tale of the minor catastrophes that mark Tristram's life (all of which serve to frustrate his father). Tristram's Uncle Toby—with his own set of catastrophes—has his own storyline. But it's all told by Tristram, who gets so distracted by tangents and back stories that the novel ends with his birth. As a result, the book has been dubbed "unfilmable." (To me, it also sounds "unreadable." But it's a classic—and the movie they made out of it is pretty damn good!)
Anyway, all of that stuff about the novel and its unfilmable status doesn't matter, because this film is about trying to film the novel.
The resulting comedy follows the actors (nearly all Brits) as they portray themselves and the characters they're playing in the film (e.g., Steve Coogan plays Steve Coogan—an actor who's got a girlfriend and a baby, a crush on a production assistant, and a rivalry with his co-star—who plays Tristram Shandy). Modern day on-the-set scenes, like ones where Coogan tries to squeeze into a gigantic uterus, or producers scramble to re-work the entire plotline, are spliced with in-character scenes from the novel, like the mishaps marring Tristram's conception and birth.
The film, at times, resembles an insider-y DVD behind-the-scenes extra—with all the attendant gossip, romance, and competition one would expect on a movie set—and it's awesome! It also seems to be every bit as farcical and naughty as the really old novel it's based on. It seems Tristram Shandy isn't unfilmable, after all.