Casino is generally associated with the concept of investing and earning. Subverting the tradition, the free casino games have been brought out to entertain and train those who like to play solely for the entertainment quotient of slots. It is a good pastime hobby for those who obsess on casinos, but hate the risks involved. Free slots are designed in replication of real casino slots and hence the best place to practice before switching to core gambling. Rainbow Riches, Nitro 81, Frog King and Demon Master are some widely played free slot games.