One of the ways Hindus celebrate and pray is by performing a Kirtan or devotional chant. During a kirtan we sing mantras which are sacred phrases repeated over and over again. Often people become estatic while doing kirtan. Ganesha is believed to bring you success. No wonder he's so popular. To learn more about Ganesha you should find and read the Ganapati Upanishad. But I can get you started here.