As seen in Can you fit a whole game into a QR code?
The above QR code contains a complete Windows executable that will run on Windows 7 and up. It's a simple but fully playable implementation of Snake.
A QR code is a data storage medium like any other, and while it's almost always used to store ASCII text, it can also be used to store binary data. As such, virtually any computer data can theoretically be stored in a QR code provided it can fit within the size limitations.
A QR code comes in various standard sizes, the largest being version 40 which can store up to 2,953 bytes (roughly 2.9 KB) of binary data. The above code is not quite that large, it's only storing around 1.4 KB of data (shrunk down from 3.2 KB with Crinkler, slightly larger than the executable shown in the video because I decided to add a little more functionality).
Method 1: Webcam (automatic)
You can treat this QR code much like a QR code in the real world by using your computer's webcam to read it (e.g. after loading this page on a phone or printing the QR code out). For this, I recommend using zbarcam. I've included a download link with everything you need:
Method 2: Webcam (manual)
This method is the same as the above, however if you'd rather input the commands manually than running my script, go for it:
zbarcam --raw --oneshot -Sbinary > snake.exe
The arguments used are as follows: