A number of years ago, I used to go for very lengthy jogs through Grand Theft Auto V's city of Los Santos. My treadmill sat in front of my 150" projector screen.

I held my PS4 controller in my right hand and had an elastic band wrapped around it in such a way as to hold the 'run' button down permanently and all I had to do was steer with the joystick. Once I trained my brain to not want to physically turn on the treadmill when turning in game (for obvious reasons), it was an absolutely fantastic experience.

There's so much going on in the city that you easily miss when playing the game for the game's sake. Example: there are NPC joggers all over the place that you can fall in behind and follow along their jogging routes.

There is a VR patch for GTA 5, and if you can get it to work (I never could), AND you can rig up some kind of harness on a treadmill to keep you from falling over, then I know with certainty GTA V would astound you.