(Clockwise from top) A still from The Lord of the Rings; Keanu Reeves in The Matrix; a still from Harry Potter and the Prisoner of Azkaban

If you have a great idea, why not make the most of it? When a movie turns out to be a cash cow, rather than let it run dry, film-makers now are quick to jump on to the biggest money-spinning bandwagon of the minute —video games.

Catwoman, Spiderman, Batman, Superman, Lord of the Rings, Harry Potter, The Matrix are just a few of the hot screen flicks that have made their way on to the interactive platform.

The content is as dynamic as the medium. For example, for a film series like Harry Potter or Lord of the Rings, there are a number of different games. Harry Potter and the Prisoner of Azkaban, Chamber of Secrets and Harry Potter: Quidditch World Cup are just a few of the options that have been released to piggyback on Potter’s magic at the box-office.

It is not all about the special effects either (though, of course, they are integral to the fun). The games are equally elaborate in terms of plot. In Prisoner of Azkaban, for example, players can choose to become Harry himself, Ron Weasley or Hermione Granger, in order to make the most of each of their skills. Sirius Black and the Dementors, Buckbeak and the Marauder’s Map all appear in the game version, aimed at the young, as well.

Or, swing like Spidey does, invite the manufacturers: “Patrol the streets and skies of a living, breathing, massively modelled Manhattan, scaling buildings, slinging webs, fighting crime and confronting numerous villains, including Dr Octopus (Doc Ock). Prepare to go wherever a spider can as the game transports you off the silver screen into a larger-than-life adventure all your own.”

And for a real touch of New York (okay, NY before Guiliani), there are ambient challenges as well: “Face the responsibilities of a super hero -- take time out from your main missions to foil random crimes in the streets.”

Not only that, the producers also create variations for different platforms, like Sony Playstation, GameCube, X-Box and Activision, to make sure they are accessible to all.

Elaborate marketing machinery is deployed to capitalise on the craze. The Matrix game, for instance, was launched on the same day as The Matrix Reloaded.

But is it worth all the muscle behind such a logistical feat? Not necessarily, warn industry experts. Warner Brothers Interactive Entertainment senior vice-president Jason Hall has been quoted as saying that he would penalise developers who made “crap games” out of film properties.

Scott Miller, CEO of Dallas-based 3D Realms Entertainment, and the man behind classic games like Duke Nukem (which, incidentally, was in the pipeline to be turned into a film) also warns against trying to turn every winning film into a movie. Apart from children’s games (like Harry Potter) it is wrong to assume that a good film idea translates well into a game.

There are three must-haves, Miller advises, for a film to transcend its space into the gaming universe — a rich and broad world to be explored; a compelling character that people look up to; “a built-in hook that hasn’t been seen” in a game.

Miller’s choices for the best fits on these grounds are Spider-Man, Star Wars, Lord of the Rings, James Bond and Indiana Jones.

But a quick look at the digits might clarify the mad scramble to grab the gaming pie. Americans might love their movies, but money spent playing games at home and at arcades has been known to outstrip money made on movies (in 2002 by as much as $ 1 billion!).

So, we are likely to see far more crossovers from both directions — games into films a la Lara Croft and every big-ticket film into a game.

So, if movies be the food of games, play on!