ROBLOX

Roblox (stylized as  RŌBLOX) is a  MMOG created and marketed toward children and teenagers aged 8–18. In the game, players are able to create their own  virtual world, in which they or other members may enter and socialize within the blocks of varying shapes, sizes, and colors. [4]  Games on Roblox can be  scripted using a  sandboxed edition of  Lua 5.1 to affect events that occur in-game and create different scenarios. The company's main source of revenue comes from players buying Robux, the main virtual currency in the game, and from players buying " Builders Club" access, a status which gives virtual benefits to users. Players who have created an account may purchase either  Builders Club,  Turbo Builders Club, or  Outrageous Builders Club, otherwise known by users as  BC, TBC, and  OBC, respectively.

For more info:
https://en.wikipedia.org/wiki/Roblox

Members in the Hangout which uses it:
RETRODeception (Marcus) (Cob4lt's real name)

realcoolguy59112 (Rottenfish)

SpiderBoyOfRoblox (Kaya)

TravisTheAnimator1 (Travis)

CeroTheRen (Cero)