I've seen this game on Flickr, and it's like the Virtual Scavenger Hunt. You post a picture that has something in common with the one above it. You can get your pictures from the internet, and tell what it has in common with the photo above it. But don't post photos of the same thing. Example:
I post:
Next:
blue
Next:
flower
Next:
pond
Okay, I'll start with this:
I post:
Next:
blue
Next:
flower
Next:
pond
Okay, I'll start with this: