While cloud gaming opens new business opportunity, it also poses tremendous challenges as the Internet only provides best-effort service and gamers are hard to please. Although researchers have various ideas to improve cloud gaming systems, existing cloud gaming systems are closed and proprietary, and cannot be used to evaluate these ideas. We present GamingAnywhere, the first open-source cloud gaming system, which is extensible, portable, and configurable. GamingAnywhere may be used by: (i) researchers and engineers to implement and test their new ideas, (ii) ser- vice providers to develop cloud gaming services, and (iii) gamers to set up private cloud gaming systems. Details on GamingAnywhere are given in this paper. We firmly believe GamingAnywhere will stimulate future studies on cloud gaming and real-time interactive distributed systems.