Buddhism

The basic teachings of Buddhism are attributed to Gautama Buddha (Sanskrit form: see Buddha for variant anglicizations) , where the title 'Buddha' is an honorific which translates literally as 'Awakened', or more colloquially as 'Enlightened'. Gautama Buddha lived and taught in or around the 5th century BC, in parts of what is now northeast India and present-day Nepal. After that his teachings spread throughout the bulk of asia, and in modern times have reached the rest of the world. Experts place the present-day number of followers of Buddhism in all its forms at between 230 to 500 million, with most suggesting approximately 350 million. According to Buddhist philosophy, existence is largely dictated by karma (literally 'action' or 'deed'). Karma connects causality and responsibility, such that our actions - which often include speech and thoughts as well as acts - influence our future experiences. Most Buddhists believe in rebirth (or strictly speaking, re-conception), and that the rebirths one experiences are usually determined by karma. However, the majority of Buddhists also hold that those who are sufficiently advanced spiritually are not bound by karma in this way; they can influence their own rebirth, and a very few can influence the rebirth of others. While Buddhists do believe that meditation is necessary at some stage, most do not believe they have reached that stage, and instead practice devotion to one or more Buddhas or other beings (except in the western world, where Buddhism has largely been adopted in a philosophical/meditational form).

 --http://en.wikipedia.org/wiki/Buddhism

There is much debate and discussion amongst scholars as to whether or not Buddhism is, striclty speaking, a formal religion like Christianity or Islam.  Regardless of whether you think it to be a philosophy or something else, it fits quite comfortably under the heading of 'spirituality.'