In recent VR and entertainment fields, many kinds of large image projection systems surrounding users are used. These systems originate from the CAVE and now are evolving as multi-projector display systems. They can effectively achieve highly immersive feelings as those users feel as if they were actually in the virtual environments projected with those systems. However, a limited number of peoples can enjoy the benefit of those systems because of the huge installation space required and cost. Obviously, these facts present significant difficulty for popularization of the projection techniques. Therefore, in this paper, we propose an effective immersive projection system with just simple projectors and convex mirrors for everyday surfaces like those in a living room. We also introduce a simple calibration method for making that system easy to use for many people.