"As you enter the dank cavern, you realize that the aspect of the light around you has changed. The light feels more organic, like the very walls around you are living, breathing organisms that project the subtle radience that allows you to see. Up ahead, a great chasm yawns breaking up the cavern so that you cannot easily reach the other side. The smell of mildew permeates the air and the ambient moisture has your entire bodies coated in a thin sheen of heavy water vapor, tasting on the tongue like lead and age, and wild disuse..." 'hey now, the rules clearly state in chapter 5, under weather and terrain conditions that....'
That's right, everyone has seen one, a rules lawyer. Just as you begin to get into the thick of a great adventure. The DM is painting the picture, your suspension of belief is running full force, you can almost feel the pummel of your sword in your hand... and then there he is. Something in the game doesn't jibe with his own belief of how the rules should work, or more likely, some advantage he has planned for through the rules and his knowledge of them is going contrary to the scenerio the DM is putting forth.
A good knowledge of the rules of a game is actually an asset to the playing of that game. By knowing the rules, you can help prevent yourself from breaking them and doing something that would disrupt everyones play accidentally. A rules-lawyer, on the other hand is someone who memorizes the rules, and more specifically, how the rules are worded, so that they can be taken out of context or contrary to the spirit of the rules in order to grab the advantage for themselves. When these specialized versions of munchkins sit down at your table, be you the player or the DM, you begin to roll your eyes, doodle on the side of your character sheet, and strongly reconsider joining that chess club down the street instead of wasting your time with the hours of arguments that you see in your future.
This doesn't have to be the case at your table. There are ways to handle such players without breeding that overwhelming negativity that comes from a disagreement with friends. I say friends, because D&D and other roleplaying games are social endeavors and thus should be something you do with friends, or at least friendly acquaintances. When friends have a disagreement it can ruin friendships so you have to be extra careful on how you approach such situations.
First, always explain to players at your table, if your the DM, that this is your home game. Yes, you are playing D&D(or whatever game your using) however, as the DM, your rule is final in all situations. Tell them that the first rule is that during play, if a conflict comes up, you as the DM will make a snap decision at that moment, not open for debate as such would distract from the game. After game time is over, you will be open to discussion upon the situation and hear the arguments on all sides of the conflict. After this discussion, you will make an official ruling in regards to that situation. This will keep you from having to disrupt your game for all the petty rules-lawyering tricks that come up. Also, this is the most mature way to handle such a subject.
Second, when you make a call on a rules interpretation, make sure you write down your decision. Record this call in your list of house rules. Make sure new players have access to the house rules reasonably. Many good DMs I know hand out a Rules Supplement Hand-Out to all players, and give them addendum sheets as new calls are made. By doing this, you insure that you have a good solid paper trail and beat the rules lawyer at their own game. Other DMs I know keep a regular website for their game, and post rules calls there, and that way any player can refer to the rules at any time.
Third, know the rules you play under yourself, inside and out. If you know not only the rules, but the context that the rules are put forth in, you will be better able to balance the rules into the game world that you intend your players to enjoy. You will also be able to anticipate any rules lawyering before it happens and have a house rule ready for those situations, or be able to bring up the really sticky rules with your players prior to them coming up in game and getting a general concensus on how the total group thinks such things should be fairly handled. Remember, the game is there for you and your players. All of you are there to have a good time and interact in a social setting.
Fourth, limit their options. I know most think that this is hamstringing the enjoyment of the group, but I don't mean it completely, but rather in a specific context. Many role-playing games have core rules, and then rules supplements and addendums, as well as optional rules. Severaly have new books coming out every month or so. It is a daunting task for any DM or player to keep up with all these rules as they are presented. Not to mention costly when your average roleplaying guide costs more than $20.00 at least here in the USA. I know that the average book in the new 4th Edition of D&D is $29.95 with some books $10.00 more.
My own personal rules for this is quite simple. First, I only allow books in my game that I personally own a hard copy of. This means that PDFs and Photocopies of specific rules are not good enough. If I don't own the book, then it's not used at my table, period. This will sometimes inspire your more rules-lawyer type players, and your heavy duty munchkins, to purchase the books as gifts for you, which covers your holiday and birthday support quite nicely as a side benefit. If they are going to rules lawyer, you might as well make them pay for the priviledge. Second, most of these new "splat" books come out in series. Each book only accents one part of the game at a given time. This being the case, I require that the entire "set" of books should be out before I use any of them. I don't mean every book for say D&D must be released before using D&D, but rather, that if a book is out giving more play options for Elves, and the game includes Elves, Dwarves, Humans, and Halflings, then the Elf book cannot be used, until the Dwarf, Human, and Halfling books are also available. Now, if my game doesn't include Halflings, then I won't require the Halfling book be out. An example of this in 4th Edition D&D is the Powers books. Recently the Martial Powers book came out for the new edition, giving additional information for Martial Character types; The Fighter, Rogue, Ranger, and Warlord. Also, this month (April) the Arcane Powers book comes out, giving additional information for the Wizard, Sorcerer, Bard, and Warlock. Finally, the Player Handbook 2 just released last month, introducing the Primal Power Source. Now, in a game where the Player Handbook 2 isn't being allowed, I would not require the Primal Power book to be out before allowing the other Powers books, but in any case, as the base or Core game includes Martial, Divine, and Arcane characters, I would require that the Divine Power book come out before I would allow the Martial and Arcane books be used.
Another note, always evaluate new books and see how they will fit your style of play and your gaming world. Just because you do own the books, and the new sets are out, doesn't mean you have to include them in your game. Take what fits, discard the rest. Do try to be fair in how you do this, but just because a new book comes out with 8 varieties of elves, doesn't mean your game world includes every type of elf available. This is true even if the Dwarf book comes out and you decide to use all 4 sub-types of dwarfs. You decide what races, classes, feats, and powers are acceptable in your game, and you don't have to justify this, just be fare about letting your players know about them.
If you follow these simple guidelines, your standard rules-lawyer will find his arsenal of disruption greatly reduced. If they are still argumentative and cannot come to a comfortable resolution, you have 3 further options you can do. 1. You can just grin and bare it. 2. You can offer to turn over the DM screen to their tender mercies or that of one of the other players, and grab some chair time on the other side of the screen, or 3. You can eject the problem player, be it the rules lawyer, or yourself. If you are ready for a break, you can quit the game, but if the rest of the players like your game, and you like it as long as the rules-lawyer doesn't keep disrupting it, then eject them and take the social consequences later on as the price of playing.