I was lucky enough to work a little bit on Gears of War 2. Once the game came out, I took it home and played through the campaign with my wife in co-op. She hadn't really played games since the SNES days but wanted to check out what I'd been working on. Once we got through the campaign - which she loved! - we started playing Horde mode together with some of her gamer friends.
One night I came home late from work. The house was mostly dark, but I heard a lot of noise coming from our living room. I walked into the room, and my wife was playing Gears of War 2 online! Not playing Horde, but playing Guardian.