I'm for games with the right themes.
So my suggestion for trying to survive in a hostile environment where you don't know who you can trust and with no clear defined end-goal is DayZ.
I gave everybody on the mumble server a copy of Tropico (because buying and running your own tropical Islands seems to be the goal of many people here), but I don't think you can play that game with many people at the same time.
Or if surviving, building and blocks are required one of the minecraft-likes is possible as well.
I haven't been keeping track of games lately so there might be more that fit our themes.