Basically, this game, which is heavily inspired by a running gag in the cartoon Pinky and the Brain, consists of non-sequitur after non-sequitur, triggered by the phrase "Are you pondering what I'm pondering" at the end of every post. I'll provide an example that explains what I mean better.
Poster #1: Are you pondering what I'm pondering?
Poster #2: I think so, Person #1, but aren't whales a bit too heavy for you to carry?
Are you pondering what I'm pondering?
Poster #3: I guess so, Person #2, but I still think your stamp collection is simply dreadful.
Are you pondering what I'm pondering?
And so on.
So, are you pondering what I'm pondering?
EDIT: I forgot, you can include the person above you's name in your answer, and it's reccomended that you include the sentence "Are you pondering what I'm pondering?" at the end of your answer. I've editted the example to show what I mean.