I'm always afraid to play games in Facebook -- partly fearing that they will spam my friends' news streams, partly that it will make it harder to leave FB when, inevitably, I do.

I'm in Google+, but mostly to reserve my name. I don't know what I want to do there, so I'm a silent loner lurker. But Google+ might become my go-to for certain games. (Jay Is Games has the lifetime achievement award.) From the Official Google Blog today (Official Google Blog: Games in Google+: fun that fits your schedule),

...Games in Google+ are there when you want them and gone when you don't.

When you're ready to play, the Games page is waiting--click the games button at the top of your stream. You can see the latest game updates from your circles, browse the invites you've received and check out games that people you know have played recently. The Games page is also where your game accomplishments will appear. So you can comfortably share your latest high score--your circles will only see the updates when they're interested in playing games too.

They're rolling them out gradually, so you may not see them yet. And their initial games offering numbers only 16, according to a screenshot. But this will undoubtedly grow.