Simple! You could, if you wanted, even do it at your desk.
Step 1: Open your Vine and get the camera rolling. (If you don't have Vine, you ARE too old for this.) Step 2: Draw an X on a piece of paper. Step 3: Label two of the resulting quadrants "no," and the other two "yes." Step 4: Place two overlapping pencils on each axis of your grid, crossing them in the middle. Step 5: Say "Charlie, Charlie, are you there?" and ask a question. (i.e., "is one of my friends going to die soon," "will I go to prom next May." ) Step 6: Scream, probably.
Where did this come from?
While it's hard to pin down an exact country of origin, Charlie Charlie (also spelled Charly Charly) has a long history as a schoolyard game in the Spanish-speaking world. According to one seven-year-old Yahoo! Respuestas thread - that's Yahoo Answers to you - kids have played a version of the "classic game" in Spain for generations.
Traditionally, this version with the crossed pencils was called the "Juego de la Lapicera" - a term that still turns up lots of creepy stuff on Google - and "Charlie Charlie" was a distinct game, played with coloured pencils. At some point in their Internet and playground travels, the two games seem to have merged. In either case, both have always had demonic or supernatural connotations; one site calls Lapicera "the poor man's Ouija board."
Why is it popular again right now?
It's always hard to say exactly why these things trend, but the latest bubble seems to have begun in late April in the Dominican province of Hato Mayor, when a local TV news station broadcast a very alarmist (and unintentionally funny) report about the "Satanic" game overtaking local schools.
From there, social media users in the Dominican Republic began tweeting, Instagramming and Vining about the game; by mid-May, the phrase "Charlie Charlie" was trending on Dominican Twitter, an easy jump away from the rest of Spanish-language Web.
Meanwhile, over the weekend, a 17-year-old girl in central Georgia Instagrammed her game and slapped it with the hashtag #CharlieCharlieChallenge. That hashtag was, apparently, all the kids needed: It's been tweeted 1.6 million times since then.
Who is Charlie, anyway?
Per various corners of the Spanish-speaking Internet: a child who committed suicide, the victim of a fatal car accident, or a pagan Mexican deity who now convenes with the Christian devil. The Mexican deity bit, at least, is demonstrably untrue.
"There's no demon called 'Charlie' in Mexico," said Maria Elena Navez of BBC Mundo.
Is this as dangerous as some of the other viral teen challenges going around?
Given that no one's setting themselves on fire, inhaling a caustic substance or deforming their lips, Charlie Charlie looks ... pretty harmless.
That said, according to popular legend, Charlie haunts players who fail to say goodbye before they close out of the game. And there are, predictably, a whole lot of people who don't love the kids-summoning-demons thing.
Why should I care? (Should I even care?!)
I mean, you should definitely care if you're seeking supernatural answers to your life questions. (Excepting questions about love, death and money, which - per certain versions of the legend - Charlie will not answer.)
Even if that doesn't exactly describe you, though, Charlie makes a killer case study in virality and how things move in and out of languages and cultures online. You'll notice, for instance, a lot of players and reporters talking about the game as if it were new, when it's actually - and more interestingly, I think - an old game that has just recently crossed the language divide.
This is also, pretty notably, yet another example of the power of the teenage Internet. Write off their little games as silly, sure - but we never trended "Bloody Mary" or "Ouija board."