Incoming!

So I found a link today of a bunch of pictures of photo bombing. What is "Photo bombing?" you may ask.

It's basically the act of being That Guy - you know, the one in the background (or, in spectacular cases, the foreground) of pictures making a funny face or otherwise adding far more to a crappy "let's all stand together!" picture?" Yeah. That Guy engages in photo bombing.

Anyway, here's a great example:
Yarg!

And here's a better one:
Brains!

Complete gallery here:
Not Entirely Work Safe