A Touch of Class

The real reason I wrote that last post was because it was for the special surprise.
This week is Caveman week here at birdflag. All my posts will be about cavemen.

Today features an interactive post. Look at the witty sketch above. The punchline is strangely absent. You can change that. You can add the punchline in the comments.
Get to it. Here's your opportunity to be a star. Best caption gets a beer.