Some games were played so long ago, or had such a limited distribution (I'm looking at you, ET) that we may not even know how the game worked! What were the rules? Who played this game? Why isn't it around anymore?
For your "Secret Game" project, make up a simple game with some sort of purpose beyond just entertainment. Then create an "artifact" (image, video, physical object, etc.) as evidence of the game's existence, and post it to the blog with 2-3 sentences about the game.
The categories of alternative games we'll be covering are listed below as a reminder, but feel free to branch out into other categories (science games, psychedelic, meditation, etc.) as you see fit!