A crystal ball?

A few days ago I introduced a new series called "Found on Flickr." Last night after a long night of helping my friend celebrate her recent birthday, I went to grab a late-nite bite to eat at Denny's. Yes, I said Denny's. You know you've been there before; don't judge me.

While "Found on Flickr" is a Thursday feature, I saw a photo opp at Denny's that was too interesting to pass up. Plus it wasn't found on Flickr but taken by yours truly:

Can you guess what this is a picture of?