Religion is phenominally easy to explain.

Aztec, Mayan, and Incans had hundreds of gods and goddesses to explain the daily "phenomina" that happened in their lives
Early Greeks and Romans used gods and goddesses to have an extrenal, agreed-upon system of faith that explained and rationalized occurrences and decisions
Earlier Europeans, particularly the Catholic church used god as a means to control the government, people, and to collect huge sums of money from the King's subjects simultaneously instilling a fear in god
Henry VIII manipulated Anglicanism as means of allowing him to divorce his many wives
And to date, many religious groups use the form of god and 'morality' interchangably to acheive what they want (issues with prayer in schools, Creationism in schools, death penalty, gay marriage, abortions, ect)

Religion is simply a means of having a bunch of different beliefs of what causes the unknown. Greek and Roman culture had gods to explain war, sleep, rain, storms, love, intelligence, and then later upgraded to mostly Catholic and protestant religions, which do not offer multi-gods (it's blasphemy now) because they have discovered means of knowing how the forementioned processes work! You don't see many Greeks and Italians worshipping Zeus and Athena now, do you? Of course they have statues, but to serve only as a reminder of what they founded many principles on.

For me, MOST (NOT ALL) religious groups harness their gods as a mean to try to get what they want in life, but back it up claiming it's offending their morals and beliefs, because we're such an immensly politically correct society, and religion and government are beginning to mix again. Many religions are severly impeding progress in sciences because they claim its immoral and evolution is crap, ect.

So you see, from a logical (and most likely "sinful" POV), religion is simply Man's way of explaining what is unknown.

And for tax breaks.

While we're on the subject, can the Flying Spaghetti Monster create a pasta dish so hot and delicious that He Himself cannot eat it?