What is considered by some to be the first video game — Tennis For Two — was played on an oscilloscope at Brookhaven National Laboratory in 1958. Fifty-six years later, oscilloscopes can still play video games — in this case, Quake.
Finnish modder Pekka Väänänen got Quake, the 1996 landmark of PC gaming, to run on a Huawei V-422 oscilloscope. You can see it in the video above, which shows a playthrough of Quake's first level.
Oscilloscopes measure electrical signals, so the video output here is some kind of weird cross between vector graphics and a Pink Floyd laser show from 1983. It's not the only piece of highly specialized scientific equipment to run video games, either.
A more detailed technical report on how this all works may be read here.