What's the difference between an homage and a rip-off? Intent. If the goal is profit, as it clearly is in the catalog of "mockbusters" from The Asylum – The Da Vinci Treasure, Snakes on a Train and the upcoming Alien v. Hunter – we tend to pre-judge the result as greedy and crass. 

Asylum co-founder David Michael Latt defends his company's work in a "New York Times" interview, saying "I'm not trying to dupe anybody...Other people do tie-ins all the time; they're just better at being subtle about it. Another studio might make a giant robot movie that ties into the Transformers release and call it Robot Wars. We'll call ours Transmorphers."

But copycat filmmakers who clearly love and respect the source material get a pass. Chris Strompolos and Eric Zala spent seven years, beginning when they were in grade school, on a shot-by-shot recreation of the first Indiana Jones film, calling theirs Raiders of the Lost Ark: The Adaptation. Now it's a cult hit, screening around the country.

And there's even a middle ground, explored in Michel Gondry's new film, Be Kind, Rewind. When Jerry (Jack Black) accidentally erases every video in the rental shop where his friend Mike (Mos Def) works, the two team up to replace the films with homemade versions.

Black was interviewed last year on Rotten Tomatoes and told Fred Topel "We were under (Gondry's) strict orders not to watch any of the movies again...Just do what you think it is based on the commercials you had seen of the movie because he wanted it to look that way."

And it does, as the trailer reveals. The slapped-together copies of classics like Ghostbusters and 2001: A Space Odyssey look worse than your average cell-phone video. And they're a lot funnier.