It ranges greatly. But I probably get around 10 a week. Most of this is on the PC. My wife and I play a lot of World of Warcraft. That is followed closely by starcraft and Diablo. However, my console gaming is probably just 1-2 hours a week. My gaming number is just as high as it is because it is a shared interest between me and my wife for PC games. If not for that, the number would probably be between 1 and 4 hours.
It is interesting to see how few hours most collectors seem to get. I know I like retro games specifically for their short play time. When I do get a few hours to play, I like the games that are short. Most platformers can be completed in under an hour once you know how. Then, I have just one or two games that are my games of choice.
I'm missing out on a lot of classics due to the hours needed. I played a little of Mass Effect. It is clearly a great game. However, I just can't find the time.