The surprise success of "Diary of a Wimpy Kid" at the box office this weekend -- it earned nearly $22 million, beating out the blazing originality of "The Bounty Hunter" and "Repo Men" -- shows much about the state of contemporary box office (and not just that a well-made movie can actually come out this time of year).

For one thing, it demonstrates that audiences may finally be getting tired of Jennifer Aniston (we've heard that before, so fingers crossed). For another, it shows that a well-known title or brand -- the movie is based on Jeff Kinney's wildly bestselling children's graphic-novel series -- is these days increasingly likely to trump a well-known actor, as several pundits have noted.

But maybe most strikingly, it proves that books aimed at pre-adolescents can be turned into successful movies.

We've heard that one before too. Observers have spent the better part of this past decade of "Harry Potter" touting a post-Potter boom at the movies. But children's books -- especially those aimed at the pre-teen set -- generally haven't caught on at the multiplex. "Lemony Snicket's A Series of Unfortunate Events," based on the literary mega-phenomenon, flopped.  "The Golden Compass" helped sink New Line as a studio. And just last month, "Percy Jackson and the Olympians: The Lightning Thief," based on Rick Riordan's bestselling fantasy series, generated more rain than thunder (though it fared far better overseas).

With "Diary" (and, in a somewhat different sense, with "Alice in Wonderland"), there are signs that the post-Potter boom is finally here. "Diary" producers pulled off a well-regarded pre-teen film despite a smaller budget than many of their more action-oriented counterparts. And they did so by showcasing a central character who's roughly the same age as much of the film's target audience. (The conventional wisdom among producers of youth-skewing movies is that most kids in elementary school and junior high want to see older characters, a la "Twilight" and "Pirates of the Caribbean").