This can works in any 3d program and can be used for nearly any game, program or whatever you like
Note that this is for beginners, not really for pros (since this may give the impression that you are unprofessional).
Just follow these steps:
1. create a sphere
2. copy the sphere and enlarge
3. make it black and put it over the other sphere
4. select all faces, invert them and merge the two spheres together
..and there you go, the effect of a simple toon-shader.