One of my most useful tools as a GM is my d6 labeled "Yes" on 3 sides and "No" on the other 3 sides. It's my Yes/No Die, and it solves all sorts of questions in combat. Between the rogue and the oracle, does the mindless monster attack the rogue? Is it the wounded orc that falls into the pit? Are you closest to the statue? And so on, and so on. As a recent experiment (and as a playtest of an adventure where I needed to test the story rather than the rules), I invented a whole gaming system based on the Yes/No Die: Yes/No Adventures. Here it is in its entirety, complete with characters:

YES/NO ADVENTURES

Basic Rules

Get one of those dice with the sides reading “Yes” and “No.” It’s more fun than a coin, but functionally identical.

To take an action, ask a yes or no question and roll the Yes/No die.

No asking the same question twice in a row or gaming the system.

You’re professional adventurers, and have whatever equipment and preparations seems reasonable for a professional adventurer. If in doubt, ask whether you have a thing and roll.

Combat Rules

In combat, the GM picks the most sensible person to start (which might be the GM) and then goes around the table. Mix this up.

When you attack something, first ask “Do I hit it with my weapon/spell/item?” If the answer is “Yes,” then ask either “Do I kill it?” or “Do I knock it out?” as appropriate for the attack.

If you hit something and don’t kill it or knock it out, there usually isn’t any effect (but might be, if it’s a poisonous or other strange attack).

Fighter

When asking whether you succeed at some athletic endeavor, you can reroll the die once.

Equipment: Longbow, magic sword, plate armor

Magic Sword: When asking “Do I hit it with my weapon?” you can reroll the die once.

Plate Armor: When asked if something kills you, you can force a reroll of the die once.

Cleric

You can ask the question “Do I heal his/her injuries?”

When asking whether you know about something religious or extraplanar, you can reroll the die once.

Equipment: Mace, plate armor, balm of resurrection

Plate Armor: When asked if something kills you, you can force a reroll of the die once.

Balm of resurrection: You can ask “Do I bring him/her back to life?”

Rogue

When asking whether you succeed at doing sneaky stuff, you can reroll the die once.

When asked if a trap hits you, you can force a reroll of the die once.

Equipment: Hand crossbow, poisoned rapier, magic cloak

Poisoned Rapier: When asking “Do I kill it?” you can reroll the die once.

Magic Cloak: When asked if something hits you, you can force a reroll of the die once.

Bard

Once per ally per turn, you can ask “Do I inspire him/her to success?” If the answer is yes, the ally can reroll the die.

When asking whether you know about something, you can reroll the die once.

Equipment: Hand crossbow, fancy cloak, mithral armor

Fancy Cloak: When asking “Does he/she want to do what I say?” you can reroll the die once.

Mithral Armor: When asked if something kills you, you can force a reroll of the die once.

Wizard

Once per enemy per turn, you can ask “Do I magically confound him/her?” If the answer is Yes, the enemy must reroll the die.

When asking whether you know about something magical or historical, you can reroll the die once.

Equipment: Quarterstaff, wand of magic missiles, armor spell

Wand of Magic Missiles: When asking “Do I hit it with my magic missiles?” you can reroll the die once.

Armor Spell: When asked if something kills you, you can force a reroll of the die once.