So, I'm making a game that's inspired by X-Files, and I want to put some Mulder and Scully quotes in it.  Does anyone know what rules I have to follow to make that legal?

The current text looks like this:

MULDER: Do you really think that was a coincidence?
SCULLY: I don't know what it was.
    -The X-Files

So, attribution to the show (but not to the owners of the relevant rights), literal dialogue from copyrighted broadcasts/recordings, and references to the names of (I assume) trademarked characters.  Is this good enough?

I have no intention of trying to secure relevant permissions at this time.  (I can't imagine there exists any incentive for the relevant people to give them to me.)

Thanks,
-David

This is the sort of territory where Americans always remind you that they are not lawyers. I'm not either, and obviously recommend either asking a lawyer or researching the original sources pertinent to your own jurisdiction to your own satisfaction if and when you're going to actually apply this information in practice. I can only tell about my own conclusions, based on my own research, when I've figured out similar situations. This non-lawyereness does not particularly prevent me from saying my piece, what with believing in every citizen having a right to try to understand and apply the laws that govern him. Of course in my case those are mostly Finnish laws, so they're only useful for you insofar as our legal systems have similarities in this regard; 85% of the time western countries tend to conform in major points of copyright and trademark law due to international treaties.

Regardless, the short answer is that you need to make sure you don't run afoul of trademark law and copyright law. The former is mainly a problem if you're planning to use the IP in question on the outer covers or advertising materials of your product, where a customer might see it and associate your product wrongly with the other person's IP. In the case of a roleplaying product one might argue (I would) that convention scenarios and such could fall under this sort of usage. The latter is a problem, speaking roughly, if you're using the other person's IP to present their creative work or to construct a creative work of your own as a derivative of their work. Mere reference is not prevented by either of these laws, though, when it is necessary to actually discuss the work you cite.

Looking at the above principles, I wouldn't have any problems personally with putting an extensive discussion of the TV series into a roleplaying book if it was somehow pertinent to instructing my players. Using color quotes, especially if it was extensive, is a more grey area, as it's obvious that you're doing it just for the aesthetic effect. One pertinent quote from one show would be easy to represent as a practical reference (which would fall under fair use), but if you're using dozens of quotes from the same literary work, it could be argued that you're actually constructing a derivative work that uses the pure poetry of ambiguous X-Files dialogue to fill an aesthetic hole in your own work. So basically, the issue is whether your quote is there to illustrate a point about your game, or whether it's there to provide the aesthetic value it did in its original context. (Incidentally, if you use a lot of quotes from X-Files but frame them in a manner that provides new aesthetic pleasure that is only tangentially related to the original, then you're just using the original material as a basis for a new work - which is also permissible; it's the same situation as when a pictorial artist cuts lots of small pictures out of a newspaper and makes a mosaic out of them: the original pictures are not used for their own aesthetic virtue, but only as bulk material for a new work.)

These principles get potentially very grey when your game concerns X-Files specifically, and only X-Files. While it is not illegal to make a game that "produces stories just like X-Files", and it's not illegal to discuss the contents and structure of the series in your instructions for play, it's also quite easy to end up quoting so much dialogue and stills from the show that your work actually could be considered an aesthetic derivative. It's up to you how close to the border you want to go with this sort of thing. Only ever having direct quotes where you substantially need them to lay out your game would be the safest; for instance, not quoting dialogue unless you want to show an example of how proper X-Files dialogue never says anything. Not having a still unless you want to show how the camera angles should be planned. Functional use only, not aesthetic. This would all be fair use in my legal defense plan, similarly to how an academic paper on literary or visual arts might cite quotes and stills from a tv show to illustrate the points it is making; an emulative rpg is ultimately very similar to such research, as both are concerned with analyzing the narrative structures of existing work.

Still, if you're only going to have one quote, I wouldn't be worried. (Unless that one quote was a self-contained poem.) Even if it was pure aesthetics, it'd still clearly be a fair homage situation with just one quote, and an explicit reference to important prior art your work builds upon. Trademark is still a concern - if that one quote was in the back cover of a book sold in a bookstore, you'd almost certainly be flouting the trademark law, considering how high profile that characters of Mulder and Scully have.

As for disclaimers - those don't do anything under the Finnish law insofar as I know, but the Americans are very trigger-happy with all sorts of cute disclaimers about how they don't own the trademarks they reference (but somebody else does), how they aren't profiting from the sales of this work anyway and all other sorts of stuff. Apparently these disclaimers do something in the USA; perhaps they have something to do with defenses against trademark dilution, for example. On the other hand, I understand that claiming trademarks for somebody else is something that implies you've asked for permission to use - and the owner has required you to print that "Trademarks X, Y and Z are owned by thisandthatcorporation" declaration. I have no idea how much sense it makes to put that sort of verbiage in your product when you haven't even asked for that permission.

Thanks, Eero.