One of the latest WebVR experiments puts an emulated Windows 3.11 terminal in a virtual space. In it, you can play Minesweeper, Solitaire, and generally mess around. Because it’s a WebVR demo, certain browser, OS, and VR headset combinations will also work, in case you wanted to feel like you were actually in front of a beige box.
If you’re using it without WebVR, then it will appear as a static 3D scene. Make sure you enable mouse pointer lock, because you will need to use the virtual mouse pointer, not your actual mouse pointer. It will ask you when it’s loaded and focused, but your browser will probably require you to click allow or something.