Call me basic but the game I run the most is Super Mario World. I grew up playing the game competitively with my brother, and I think maybe finding the speed running community has since reactivated that competitive nature within me. Plus the controls are tight and there is a lot of documentation and support. :)

I play the game about 2 hours a night; I would estimate roughly 10 hours a week. That's pretty consistent, so I would say I put somewhere between 40 - 50 hours a month into Super Mario World!