First I get a video of a friend doing something goofy but recognizable - it has to be completely unique and out of the ordinary - like chicken dance followed by the running man. Then I pick a random country - say the Philippines - and show this video automatically on YouTube to anyone from that region. Do this for a few weeks and then invent some reason to get said friend over to the Philippines. Once he's over there, every single Filipino will be pointing, laughing and likely imitating the dance. My friend doesn't understand what's going on and is perplexed why he's being targeted for ridicule.
The alternate, even more evil version, is to take this same concept but instead of a goofy dance, create a fake clip where my friend is kicking a dog or running down the street flipping over baby carriages (prop dog/babies of course). Then send him to the country where you've been running the clip and watch a mob form to chase him down for this terrible acts.
Hilarity, right? :)