Computer games are one of the most successful application domains in the history of interactive systems. This success has come despite the fact that games were ‘separated at birth’ from most of the accepted paradigms for designing usable interactive software. It is now apparent that this separate and less-constrained environment has allowed for much design creativity and many innovations that make game interfaces highly usable. We analyzed several current game interfaces looking for ideas that could be applied more widely to general UIs. In this paper we present four of these: effortless community, learning by watching, deep customizability, and fluid system-human interaction. These ideas have arisen in games because of their focus on user performance and user satisfaction, and we believe that they can help to improve the usability of other types of applications. Keywords Computer games, game interfaces, user communities, interface customization, interface design