From David Pogue, learn about Internet Memes and finally get the jokes.

In the olden days, it was simple to keep up with pop culture. There were only three channels on TV, and everybody saw the same shows at the same time.

These days, of course, not so much. There are 500 channels on TV, and you can watch anything at any time. That doesn’t mean, however, that we no longer have a common pop-culture base. We do — it’s just moved online. Show me somebody under 20, and I’ll show you someone who can laugh at “Friday,” sing the “Bed Intruder Song” or “plank” in an incongruous place.

But there are plenty of other people who aren’t getting the references at cocktail parties and in the late-night comedians’ monologues. And a certain percentage of those out-of-the-loopers might wish they had a single, concise cheat sheet of the most important Internet memes (fad concepts).

Today’s your lucky day.