Thoppu-karanam is an ancient Hindu practice of worshiping Ganapati that people perform in order to please Lord Ganesha. It is believed that thoppu-karanam is a request to Lord Ganapati to bestow wisdom, intelligence and fortune. There is evidence that ancient sages instructed their students to do this practice to stimulate their brain activity. In Hindu tradition, Ganesha is the protector of children. Therefore, this practice is especially recommended for children and is often performed in modern Indian schools. It is said to help the learning process by removing various obstacles.
see also story of thoppu-karanam: "Dharma-Chakra".