To play this game you need a blog or other website where you can easily post something (you can also play it in a web forum, if the owner allows such games). The goal of the game is to create a multi-author Choose-Your-Own-Adventure game. If you don't know these games, they are basically a story split into small pieces or stations, and at the end of every station the reader can decide what to do – like "fight the monster" or "enter the tower." Depending on the choice made, a different station is chosen to continue with different results; this goes on until the end (e.g. the player wins the game). As for the "multi-author" part, this simply means that you won't be writing the adventure alone – which can help, as having many choices means creating many, many stations.
Now, to create these adventure games – and later on play them – using Google, start off with a post title like "The Beginning of the Magic Forest Google Adventure Game." (It's important to start the title with "The Beginning ..." and end with "... Google Adventure Game." Make sure there are no hits yet in Google for your title and that it contains only up to 32 words.) Now create your first station along with your first choices. You use a link to a Google search for each choice, and this search must be of the following form:
"From the beginning to the dark cottage in The Magic Forest Google Adventure Game"
Or, as another choice example:
"From the beginning to the shabby road in The Magic Forest Google Adventure Game"
What does this mean? It means your station is named "the beginning" and this particular next choice is named "dark cottage" or "shabby road." This search is enclosed in quotes, and it will not return any continuations yet. However, for the next person to write this station, she must only include the exact words of the Google search (like "From the Traveller's Inn to the Barkeeper of the Traveller's Inn in The Magic Forest Google Adventure Game") in her post's title. And after a while, Google will indeed find it and players can continue the story at this point. If a player is facing more than a single result in a Google search, he may choose any random result he likes by looking at the snippets only.
To find new games, all you have to do is search Google for "The beginning * Google Adventure Game."