Finally got around to seeing Knocked Up last night, two months after recording it off pay-per-view, and it was excellent, very funny with a sweet undertone that never turns sappy, and some excellent performances.

Knocked Up scores biggest by avoiding the Big Artificial Conflict that wrecks almost every relationship comedy. I’m going to demonstrate this by using one of the worst movies I’ve ever seen, the positively fecal The Object of My Affection starring Jennifer Aniston and Paul Rudd. Rudd, who is also in Knocked Up plays a gay man who is roommates with Aniston’s character. They become friends. She falls in love with him. He’s still gay, but there’s some chemistry happening. She becomes pregnant (not by Rudd’s character) and wants him to help her raise the kid. Then there’s a pivotal scene in his bedroom when they’re just seconds away from a kiss … and the phone rings, and hey, whaddya know, it’s an ex-boyfriend of his who wants to get together. And that’s it – they end up apart, him with a guy, her with a guy she meets a few minutes before the end of the movie. This is horrendous writing, first because it’s just lazy to end a difficult and important scene with a deus ex machina phone call, and second because there was a much more important reason why the characters couldn’t get together – because HE WAS GAY.

Where Object and so many movies fail, Knocked Up succeeds. Yes, Alison and Ben break up, but it is an inevitable occurrence, the result of a slow build of tension that explodes in a hilarious, foul-mouthed screaming match that starts in a car and ends in a gynecologist’s office. It also serves as a pivotal plot point that gets Ben to grow up, which, frankly, I’d been waiting the whole movie for him to start doing. And, most importantly, Apatow picks up the movie’s pace after the split, avoiding the typical slowdown in most relationship comedies that comes after the writer has forced the two people apart and now needs to spend a solid 45 minutes showing us how miserable they are without each other. We don’t see Alison or Ben miserable; we see both of them acting responsibly, and we see Ben doing something about his half of the problem. What a decidedly grown-up concept.

The main actors were all very good. I’ve been a Katherine Heigl (Alison) fan since “Roswell” – the season-three hairstyle sold me, since you can’t pull that look off if you’re not flat-out gorgeous – so I didn’t need much convincing on that one. Seth Rogan (Ben) was outstanding as a very unlikeable guy who, it turns out, is more clueless than jackass. (Speaking of which, I don’t get the criticism that the movie is “sexist,” which Heigl herself even intimated in a recent Vanity Fair interview. Ben starts out as a goofball and a ne’er-do-well, he’s depicted as reaching in the relationship until the very end of the film, and his friends are socially retarded. Alison’s successful, smart, and funny. This is sexist … how?) Leslie Mann and Paul Rudd are hilarious as a vaguely demented married couple whose relationship is slowly disintegrating under the weight of two kids and his busy job; Rudd’s scene in the Vegas hotel room with Rogan was one of the film’s highlights. And Harold Ramis has a great cameo as Ben’s father.

The movie does have some missed notes and unevenness. Joanna Kerns as Alison’s psychobitch-mom-from-hell was jarring, and she appears just once as a sort of comic foil and doesn’t resurface until the closing credits. The Asian doctor was just as one-dimensional before a jarring character change near the film’s end – it’s like he was there for the joke, but then Apatow needed him to be more normal, so he altered the character. In general, Apatow uses his one- and two-scene characters as sharply-defined props to create slightly forced comic moments, when his specialty is building comedy from real situations. I thought ending the movie with a scene where Alison sees the nursery Ben set up would have been perfect, but that’s just me being sentimental. And I wish that the idea that Ben is a skilled handler of people – he wins two interpersonal negotiations near the film’s end by using conciliatory tactics in one and firm tactics in the other – had been explored a little more earlier in the film. If it was a latent skill, fine, but show us a glimpse earlier on rather than having him emotionally tone-deaf in all of these situations where he’s with Alison and says the absolute worst possible thing.

If you can handle some vulgarity and don’t mind marijuana usage as a running gag, Knocked Up is worth the rental. But if you’re married with kids, it becomes a must-see, because there’s another layer of humor that you’ll get that the non-parents in the audience just won’t quite appreciate.