That is not a ponzi or investment site with a return or mining, but a game type site, where you have PVP or player vs site style and you can earn btc?
Has anyone seen something like that?
This is investor-based games in fact. What you are talking about has nothing to do with investments so I assume you may better look into games and rounds forum.
Game - physical or mental activity or contest that has rules and that people do for pleasure
If investing and sitting/sleeping and waiting for money to come is game pleasure, then im wrong.
There are many ways to create a game where you can invest in it and earn by competing with others,
but like user said abowe, there are not many left if any
coindoubler, hyip, cloud mining (fake)... all of this site are not a "game" but a just a way to help a thief to steal some btc.
some times users try to be lucky and play with this sites but they are only going to waste money, I can't see any pleasure in this "games"