Wizards of the Coast, a game producer and manufacturer who made a name for themselves with the Magic: The Gathering trading card game and eventually took up carrying the mantle of the role playing granddaddy, Dungeons and Dragons is trying to change the face of the paper role playing community with it's Open Gaming system.
The concept should sound very familiar to those who've heard of Open Source software. The core rules of the game (called the System Reference Document) are covered by a GPL-like Open Gaming License. The concept is so similar that the Open Gaming Foundation (presumably a GNU-like organization) even suggests that the GPL and Free Documentation License can be used to the same effect. These core rules can be freely distributed, modified and changed, provided the same freedoms remain intact for the new drafts and are identified as such.
Dungeons and Dragons 3rd Edition as well as the Star Wars RPG have both been released under this system. It is obviously presumed that other games will follow suit and join the party, collectively referred to as the d20 System. Wizards of the Coast claims that the reasons for doing this are primarily to breathe some life back into the sagging paper role playing game market. They point to the "proliferation of different, incompatible, core game systems" as reasons for the market dip and hope that by consolidating these into one more closely related system they can strengthen the market and (presumably) allow game designers to focus on the nuances of the game environments and the gamers on actually playing instead of learning how to play.
At first, this seems pretty well thought out. Many young role playing enthusiasts turn their enjoyment of complex, collaboratively built stories into a fascination with complex, collaboratively built software systems so the relationship the two communities have is already established. If one group can embrace a concept, the other is likely to be able to do the same. Also the open nature of the d20 system seems to merely apply what gamers themselves have always done (many role players have a few "house rules" in their games) to other developers as well, freeing them from the burdens of not only creatively offering new concepts and worlds but non-infringing rulesets as well.
Of course, now Wizards of the Coast is in the same boat as Red Hat. If they give away the rules to the game, how can they make money off the product? When TSR ran the show, they sold the basic rule books (The Player's Handbook and the Dungeon Master's Guide, IIRC) at around $20 each. Aside from dice, which neither TSR nor WotC has a cornered market on, these products were essential to play the game. There were other products available such as miniatures, modules, add-ons, expansion kits, novels, and pre-made adventures, but these weren't essential to play. Assuming that most players would eventually buy at least one of the basic rule books (in-group sharing of books was probably a common phenomenon) they could expect at minimum $20 from each player. If that is taken away, WotC must rely on the nonessential purchases to keep them in business.
To combat this, they seem to have mostly done away with the Dungeon Master's Guide as it has been replaced by the freely available System Reference Document. But they haven't included everything needed for play in this essentially GPLed rule set. There are no explanations for creating a character to fit into the world and no details for how to apply experience gained through gameplay. These non open aspects of the game are proprietary, unchangeable and only available in the new Player's Handbook. This combination of open standards and closed requirements may rub philosophically charged Free Software people the wrong way. It is analogous to offering a free Operating System but requiring the purchase of a proprietary initialization script. The free part does you no good without the non-free part.
And this is where the system would seem to develop ugly cracks. If the SRD and Open Gaming in general were designed to allow for improvement of the game system as a whole (WotC claims that deviations which are superior and more popular to the published version of the SRD used by Star Wars and D&D will become standard by default) and advancement of the gaming community in general, how long would it take before no one bought official Dungeons and Dragon's merchandise at all? All it takes is someone developing character creation and experience allocation rules in a similar manner that game designers have always done (all role playing games pay homage in some way or another to D&D) and releasing them under the OGL before D&D is a waste of money. If everyone can play at no cost, why would anyone play for money?
In this case all the checks Red Hat has built in to its model disappear. No one has trouble installing rules to a game in their mind, so WotC can't sell D&D support packages. It is unlikely that anyone would need mission-critical, professional level features for a Saturday afternoon gaming session. And text files are smallish, so bandwidth won't likely prohibit players from downloading megabytes worth of data; and that data is read just as easily from printer paper as from a glossy book.
Which raises an interesting question about Open Source Software. If Linux were ever made truly user-friendly, secure and stable out of the box and bandwidth were ever a non-issue... would anyone pay for something that was better attained for free?