Fantastic Facebook games and where to find them?

So I have heard that there is something called Facebook games. I have never tried that before and am a little curious. Can anyone recomend any of them and how do I access them? I am using an iPhone SE and an iPad Pro 9.7.

Forum: 

#1 As far as I'm aware they're not accessible

I believe you get to them through the messages app but also believe that none are accessible... Though I'd love to be corrected...

#2 Mafia wars

The only one I am aware of is Mafia Wars but I don’t know how to play these games in iOs. Do I need to use Safari or can I do it in the Facebook app?