Sure, it's predictable and over the top. But this is a sweet, competently executed farce, just the way they're supposed to be done.
Not the most brilliant script in the world, but in the hands of a lot of talented comedic actors, the result is damn funny. A few bits fall flat, but most don't. Sort of the inverse of the embarrassingly bad "Grownups."
I looked up Paul Rudd's assistant on IMDB when I got home, because she stole every scene she was in. Turns out her name is Kristen Schaal. Looks like she's done some bit work here and there, and is building a resume. I hope we see a lot more of her in the future; she's hilarious.