There are certain novels they say just can't be filmed, but guess what? Most of them have been. "Dune"? "Naked Lunch"? "The Virgin Suicides"? "The 120 Days of Sodom"? "Ulysses"? All done — "Ulysses" twice, even.

Call it the inability of a filmmaker to resist a good story, or call it the weakness of a producer for a property with a built-in audience, but whatever the reason, this season sees a wave of "unfilmables" hitting our screens. There's Ang Lee with the decade-in-development "Life of Pi," Lana and Andy Wachowski codirecting "Cloud Atlas" with Tom Tykwer, and the Holy Grail of unfilmed books, "On the Road," as imagined by Walter Salles.

Once upon a time, fantasy novels were the biggest challenge for filmmakers, but that's rarely an issue anymore, post-"The Lord of the Rings." Yet special effects were exactly what made author Yann Martel's "Life of Pi" such a daunting project: Studios are loathe to green-light aquatic films, which have a rep for coming in late and over budget ("Waterworld" remains a traumatic memory). Lee, the third director to attempt the project, was himself almost shut down by 20th Century Fox, but the giant wave tank he built in an abandoned airplane hanger in Taiwan for the oceanic shots did the trick.