Basically a force feedback wheel/pedals/ single or triple monitor setup allowing you to play iRacing (subscription based service) which is the most realistic sim/game I've played so far and that's just using a controller until I decide on a wheel.
You can go from simple to wild and anywhere in between.
Wildest I've seen yet
Sucks for a lot of people that don't have the PC capable of running it already, because to get a setup that can run it fluidly (150+ FPS) is a decent chunk of change for most people. If you are already into PC gaming its usually as simple as grabbing a wheel and pedals, maybe new monitors and going from there. Or like me, just plug in the Xbox controller until you get a wheel.
Here's a quick vid of my racing from earlier. Dumb fun even just with a controller. Doc's wheel setups I think would be compatible, maybe next time he opens up I can run my PC up, use my phone as a hotspot and let some people try out a few laps (If he is okay with it and the wheels are PC compatible, most are I think).