Roblox is a popular online game that allows you to create virtual 3D worlds out of lego-like pieces.
It's easy to get started. Simply register online at the official website where you will be able to create your own avatar. These avatars can be customised from head to toe and used to help you build your environment. Play against others online and in a countless number of worlds.
The game is free, but you may also upgrade to a paid version available with additional functionality. It's a cross-platform too, so you can play on a variety of devices against others, including Android, iPhones, PCs, MACs, and Xbox. It's also compatible with certain with VR (Virtual Reality) devices.
Roblox is also available for iOS. Versions for Windows, MAC, and Xbox can be found on the Roblox website.