I have seen the Lord save many souls (particularly children) through this. It is inexpensive, simple to use, and effective. We focus on street evangelism, but I recommend it for use in preaching the gospel anywhere. Possibly the easiest way to complete the Great Commission, you need to own one of these!
The evangecube opens doors when you are witnessing in a country where your primary language is not the spoken one. You can share the story through the pictures and if you are using an interpreter it doesn't not take long for the person receiving the story to understand how the cube works and then they are witnessing in their language to those around them. We love using this during VBS mission trips and children are a natural for using the cube to share the gospel with others; both their age and adults.