Recently digital designers have begun to integrate game elements and mechanics into non-game applications, systems, and services, to better engage end-users. This notion is named as the "gamification". In this paper, we discuss the idea of applying the gamification concept in designing intelligent environments to improve the overall user engagement. We present two case studies to better understand the effectiveness of gamifying intelligent systems: a mobile crowd-sourcing application that works as image based social search across languages, called UbiAsk, and a persuasive application for motivating users to reduce CO 2 emissions named EcoIsland. We argue that the game-based incentive methods only work with a careful design: designers should be aware that the main functionalities of the system have much greater impact than the additional gamified components, and the desired game-like user behavior requires comprehensive game-like experience that is supported by not only a "game structure" but also a "game-look" surface.