"King me, beyotch" gambit: Tactic used by people who have no idea what the hell they are doing. Not used as a deliberate attempt to set your opponent off balance, but merely due to your complete lack of knowledge of the rules.
The Back-castling ploy: An attempt to apply a rule that does not exist formally (or sometimes, beyond your own mind) to a game while in mid-play. Often done through emotional blackmail, threats of taking your twelve fallen pieces and going home, or outright deception. The reference is to castling which can only be done once per game, based on its conditions, while a person hypothetically attempting this ploy literally would insist that you can continue to castle over and over again, as long as a rook and king are in the right position.
"Thimble to B-7" tactic: Introducing not just an alternate interpretation of an old rule, but an entirely new rule that actually isn't true to the actual premise and spirit of the actual rules. More often than not, this rule has no precedent. Not necessarily a bad thing if agreed upon beforehand. If so, it is merely trying a new take on an old game. If not, it is a combination of back-castling and "king me beyotch".
The "Your Queen was always at D-4" shuffle: A combination of obfuscation and outright cheating, while still seemingly following the rules. More common for people who actually know what the hell they are doing, but still not enough to succeed by playing on equal ground.
Teabagging the Bishop: An overly enthusiastic response to a minor victory, meant entirely to demoralize the opponent and rattle them. Ties into Uber-Pawnage.
Uber-Pawnage:When you attempt to intimidate your opponent without ever presenting an actual strong offensive. It is a strategy based on winning almost entirely based upon putting forward a tremendous ego, or tricking your foe into questioning otherwise effective tactics based upon your presumed strength.
The "I Thought We Were Playing Backgammon" Strategem: Instead of changing the rules, or playing incorrectly, you decide to outright demand to play a different game entirely, which you are more likely to win. Good for the desperate and pitiful.
The "We Were Always Playing Backgammon" Trick: Game switching meeting outright deception. Hard to pull off, but very rewarding when it does.
Flip the Board: Walking away from a game...with vengeance. Often results after an ineffective attempt to introducing new rules, cheating, or changing the game. If more than one player was involved, you may or may not ruin the game for them with your departure. Regardless, you will claim victory regardless of your board position when leaving. A prized tactic for the childish.
A "My Catapault Turtle Launches Dragon Champion Into Your Castle Shattering Your Flotation Ring And Crushing Your Monsters" Checkmate: Goes beyond a "King Me, Beyotch" Gambit. They are so beyond the rules of the game, or even common sense in general, that it would take more effort to explain why they are wrong, thus extending the period of time in which you must suffer with forcing them to follow the rules, then it does to just concede defeat to their bizarre interpretation of the game. Basically, a lost cause.
The "Discourse on the Historical, and Metaphysical Implications of the Representation of the Pawn in Chess's Gameplay Dynamics, and Why This Suggests that Pawns Should be Allowed to Move Backwards" Ploy (Blinding with Bullshit, for short) : An attempt to fatigue your opponent into accepting a back-castling ploy by piling on heaps of rhetorical devices, appeals to irrelevant issues, or just outright deceit. A filibuster of fallacious justification.
The "It's Just A Game" Gambit: Justifying your own manipulation of the rules to your opponent by dismissing the overall game played as insignificant.
The Nihilistic Chessmaster: As the "It's Just A Game", accept that it is done with borderline "Blinding with Bullshit" narrative, and justifies real injustices and exploitations by dismissing the relevance of not just the game being played, but everything in general. A pawn fallen to the diagonal movement of a rook would only have fallen eventually anyway, and his trace in the universe remains just as infinitesimal as it would have been had he survived.
The "Defeat is Victory" Battlecry: When you decide that, after having already finished losing a game, that it was not only irrelevant, but that your loss is a testament to some sort of superiority in your own nature (or that you are superior despite the insignficant loss). Rare, but annoying.