ALL YOUR BASE

This is one of those phenomena you might have missed because you never knew to notice it.  But once you read the site or as much of it as you want to, you'll start seeing All Your Base every so often, and you can be in on the joke too.

Even if you don't care to start noticing All Your Base, it's worth going to the site to see the degree to which anyone with some software and some skills and some patience can fool you into believing your eyes.