This document provides an overview of several multi-user virtual environments (MUVEs) including Second Life, OpenSim, Simonastick, and Kitely. It discusses key features of each including that Second Life is hosted by Linden Labs but OpenSim is open source, Simonastick allows running a virtual world from a USB stick, and Kitely provides virtual worlds through Facebook. The document demonstrates how to access and use these different MUVEs and suggests they can be used for different purposes like community engagement, teaching environments, or content creation.