It’s a fairly memetic part of gaming culture. Google Trends doesn’t show any real interest picking up until 2007-2008, so I’m going to say Team Fortress 2 is what brought it mainstream attention, which could be completely wrong since it’s an assumption I came to in about five minutes. But it’s big enough to have programs dedicated to its proliferation and plenty of YouTube videos depicting it.
I’ll leave it up to the masses. Should an entry be created, I’ll need help from someone with a bit more gaming experience than I.