For the past year or more? Madden NFL Arcade. Admittedly, it's a terrible game. I turn game changers off, crank the difficulty, and pick the Cleveland Browns. I play it at least a few times a week, it's relaxing.. a lot of times I kick out a couple games just before bed.
It's a broken piece of shit game, the only play that covers the RB is the "Y" middle defense. Any other defensive play leaves the RB wide fucking open. The PC is terrible on pretty much every level.. run the ball on 4th and 50? Sure.. why not.
I also hate the Cleveland Browns. Brady Quinn is the QB. They are one of the worst teams in the game. My receivers are Mohamed Massaquoi and Josh Cribbs. My HB is an old Jamal Lewis. Before using exclusively the Browns I always picked New Orleans.. I also hate New Orleans.
I win every time, but I keep going back.
Before that was Baseball Advance from the GBA library. It was 2001 rosters, and I still played the shit out of it until 2011 when the cartridge finally gave out. I just haven't gotten around to buying a new one. It's the purest and greatest baseball sim out there. I've played upwards of 10 full seasons. You can't trade players, which always bugged me, but still I kept at it. I made up new names for players, pretended that the rosters were up-to-date, though it's hard to pretend their is more than 4 fields.. but it worked since I always played Seattle.