I want to try something I've been participating in on another (fountain pen) forum.
The object of the game is to post a picture of something that you think others will have a hard time figuring out. People guess, you tell them right or wrong, give hints along the way if necessary, show the object from a different angle, etc.
The winner gets to be the next person to post a "mysterious object."
It took several days and lots of hints for anyone to finally guess the object shown below. Somehow, I think the folks here will get it in a matter of minutes.