Got this idea from Hocus Focus- from the newspapers, usually near the Comics section:
Get two or three students to go in front of the class. There will be a "before and after" comparison. For the before, have the students pose in front of the class and everyone else try to remember how they look for the before. Allow about 30 seconds to get a "good picture."

The two or three volunteers then leave the room for a short time to come up with an after pose. The after pose will be slightly different from the before. The rest of the class will have to point out the differences.

Start with just 3 or 4 differences at first to get the idea of what the game is all about. Also, you might want to write the differences down on a piece of paper (sort of a check- list).

Some of the slight differences may include: Before- Sue's laces were untied..... After- they are tied.
Before- Tom is standing tall.... After- he's leaning to the right.
Before- Kyle wears jacket unzipped.... After- jacket zipped half way up.

Just use your imagination but, don't get too complicated.

I know this sounds confusing; it's a lot easier to show you the game. Hope you can understand how I told the details. It's a fun game; I played it on rainy day recesses with great success.