Zoroastrianism is a religion which was based in ancient Persia (which is modern day Iran). It both pre-dates Judaism and was present at the time of Judaism. Only roughly 200,000 Zoroastrians are around today, mostly in India, Iran, England, and the USA. Zoroastrianism is a dualistic religion, meaning that they believe in a tension between all good (Ahura Mazda) and all evil (Arihman). Time is about the battle between good and evil, and in the end good is bound to win.
The prophet Zarathustra told the people that the earth was made of fire, water, air, and earth, and all of those things were sacred. Its believed that people should maintain the purity of the elements and Zoroastrians have very strict rituals to do so. Fire represents the purity of Ahura Mazda, the ultimate good, and thus fire is very important to the religion.
For instance, they believe that dead bodies pollute the earth. There is an elaborate ritual for disposing of dead bodies. Bodies are put on top of a "Tower of Silence" where they are up high and birds can pick the bones clean. The bones are then buried once they are free from debris. Also, when women were menstruating they were believed to be polluting. They would be locked in a common room in the town where they would not be touched by light and could not pollute the earth.
The scriptures of the religion are called the Gathas, the most famous of which is Zendaresta. Zarathustra is called Zoarastar in Greek and is believed to the prophet sent to save the world. It was said that Zarathustra was able to survive fires, had been put in a basket and sent down a river and survived, and survived various other tests due to divine intervention.
The religion believes that humans are essentially pawns of the cosmic struggle between good and evil, but also have free will. There are Six Aspects of Goodness that Zoroastrians believe are essential to possess. They are righteousness, devotion, desirable dominion (making the world you live in better), wholeness, and immortality. The Magi are the high priests and are intermediaries for complex rituals. Often rituals were written in a complicated ancient language called Pahlaui which the priests could read and most others couldn't.
The followers of the Zoroastrian religion do not promote conversion, in fact there is a debate going on amongst current followers about whether that is a good idea. The religion has been considered elitist in the past, which is a problem now that its followers are dwindling. Traditionally, people cannot convert to the religion, both your parents must be Zoroastrians first before you may be one. There was a problem in England when the government realized that some Zoroastrians were basically resorting to getting Zoroastrian mail order brides because there was such a problem finding mates. This was mostly effectively curbed, but the religion may have to resort to letting Insiders in if it doesn't want to completely die out.
Source:
Lecture from UCF Dr. Stockdale ASH3222