Not sure about a ATV sims, but there's an awesome motocross game out. Well,
actually its been out for years. I think about 8 years or so. It's motocross
madness 2. Its a great game and it was heading in the right direction until
rainbow studios gave up on the pc market and headed towards the console
gamers.
I still play it to this day and making tracks is a breeze.
