Today's topic is making rulings on the fly as a GM--specifically, calling for rolls that aren’t necessarily covered by your system of choice. You don’t need (or want!) a game to give you a mechanic for every little thing. Once you’ve grasped the basic resolution mechanics of a game, you can apply that knowledge to resolve any crazy thing the PCs come up with to try. I’ll use the current incarnation of D&D as an example.