Just a random thought.

Business cards are both a good and bad format in regards to new players to RPG's and in regards to simplicity as:

* They guarantee the game is simple (Good for new players and simplicity) But...

* They don't offer enough space to fully explain everything, with all the flowery and in-depth language that communicates the rules best, (Bad for new players and simplicity)

I like this format for something like MOSAIC Strict, building the kind of RPG you want to play by compiling a small, focused collection of modular rules and mechanics.

This is a great format for getting yourself to put a finished project out there. You don't have room to bog yourself down on lots of details and feature creep.

It really gets the dev thinking and forces the game to focus on core elements, clearing away much of the “fluff” that one can find in many games made these days.

I love the modular nature behind this. If you can fit a modular system on a business card (or index card), you can then just create a mosaic of systems at the table to suit your own adventure.