Kenahorah-Poo-Poo-Poo: a colloquial Jewish/Yiddish custom that we grew up with. Kenahorah is Yiddish for - keep the evil eye away. You can tempt the evil eye by saying positive or happy things. Poo Poo Poo - or "Poo Cubed"- simulates spitting three times to avoid the evil eye. You can also hold up the thumb and the pinkie while you are "poo"-ing.
More background from The World of Jewish Superstition:
Jews also take names very seriously.
One longtime Ashkenazi Jewish
tradition is to name children after beloved - and dead - relatives; you
rarely find a Jewish "Junior." One reason for this is simply to honor
dead, but another was that a child with the same name as a parent was
considered a challenge to the demons, or even the Angel of Death, who-upon
entering the home - could confuse father for son and take the wrong person.
Rabbi Shraga Simmons, a rabbi from Aish HaTorah (a Torah institution in Israel), said that these habits have practical applications. "It's a good idea to be careful about boasting of our own success, because the sad reality is that many people are jealous, and in order to feel better they will secretly wish for you to lose what you have," he said. "Flaunting oneself simply invites the possibility of 'evil eye.' "
The evil eye - in Hebrew, ayin hara - is a concept in itself. For some Talmudic rabbis, it was a literal thing: certain people, with just a glance, could "turn men into 'a heap of bones.' " But more often it represents ominous tidings: That's why Jews tie a red bandel(string) around a baby's crib to keep away the evil eye. You spit three times to keep away the evil eye. The phrase kenna hora - the colloquial pronunciation of kein ayin hora that roughly translated as "may the evil eye stay away" - is often spoken as a kind of talisman.
For Frankel, the evil eye represents a quintessential dilemma for monotheistic religions: what is the nature of evil. "If you believe that there's only one God, then that God has to be responsible for evil as well as good," she says. "Deep down, I think many people can't reconcile this notion. So the evil eye and other superstitions were created to account for evil in the world."