Kurt Vonnegut wrote Cat's Cradle which described the fictional religion of Bokononism. To find out more about Bokononism, you can either read Cat's Cradle or visit this site, which has all of the canonical quotes from the Book of Bokonon. While the full precepts and principles of Bokononism are fairly technical, yet satiric of all organized religions, there is truth in the lies of Bokononism.
Foma are the harmless untruths that get us through our life. The only canonical foma in Vonnegut's writing is from his essay collection Wampeters, Foma, and Granfalloons where he uses as an example, "Prosperity is just around the corner."
Other statements that might qualify as foma include:
Hard work gets rewarded.
Anybody can grow up and become President.
Your mother really likes the art you bring home from summer camp.
These lies are different from the three biggest lies (check's in the mail, etc.) because we need these lies. In a world of six billion people, who thinks their job, family role, social position, is unique and necessary? No one is irreplaceable, yet we all deserve some dignity and mutual respect. Even if that is just a foma as well.