The GameMaster's Apprentice is an adventure crafting and arbitration tool I designed to support any role playing genre and any game system. The simplest explanation of how to use them is also the best: Just draw a card (or more than one), look at the content on it, and use one or more of the 14+ randomizers to inspire something in your game, be it a character trait, a random encounter, or an adventure seed!
For a more complete look at the cards, their possible uses, and all the content on them, the free download here at DriveThruRPG includes the quickstart guide, printable how-to tip cards, and the full instruction manual. The ALONe: A Solo Game Engine Beta, a GM emulator that lets you play any game solo, is also free, and includes a half-deck of the genre-neutral base deck in Print-n-Play form.
And if you want to see them in action (both before-gaming and on-the-fly), below are some videos I created during the GMA Kickstarter campaigns; they demo story generation and using the cards as a game engine, with both the base deck and the fantasy deck.