Several prophecies (beware: Lord of the Iron Fortress spoilers)
I've actually been making extensive use of prophecies in my game. Its a bit of a hybrid between the WotC adventure path and the draconic Rage going on in the Forgotten Realms, and there are all sorts of potentials to weave in the theme of destiny. For example, one player decided to play a sorcerer/dragon disciple... and I've been teasing him for a while with various dreams, strange texts, and run-ins with strange enemies--because apparently he can trace his ancestry directly back to Ashardalon....
And various other such things.
I have a lot of fun with the prophecy angle, and my players seem to enjoy it as well. However, I have found them to enjoy it in a very passive fashion, which can sometimes be frustrating. I know that, if I were a player and ran into the kind of prophecies that I throw out there, I be hell-bent on figuring it out. I would be using divinations, tracking down sages, and constantly filtering current events through the lens of the prophecy for clues. My players, on the other hand, seem to have more of a reaction like, "Cool. Let's move on."
To get back to your question, RangerWicket, here's an example of some of the prophecies I've used:
When spiders cease to whisper, a great war shall erupt in the deep places of the earth, and the white banshee shall claim her inheritance.
This refers to the War of the Spider Queen: Lolth's silence, the ensuing war, and the events in the
City of the Spider Queen, in which Kiriansalee (the white banshee) tries to usurp Lolth's (her mother's) power.
When the harp's strings fray and the stars of the moon rise, the city of song shall sing again.
Those well-versed in Realmslore should catch this one without much trouble. Translated, this passage prophecies that Myth Drannor (the City of Song) shall become inhabited once again around the time of the Harper/Moonstar schism.
During the days of rage, the rogue dragon shall have his vengeance upon the people. His progeny shall gather to him a great army among the greatest warriors, and that army shall cull the greatest smiths of Toril to reforge the blade that was broken. When it is finished, the Lord of Iron shall marshall his host and cut a swathe of flame and blood across the land.
This is a longer one that my players are currently teasing out. (Thankfully they do not hang around EN World, which is why I can share it.) Broken down bit by bit:
days of rage = in the Year of Rogue Dragons;
the rogue dragon = Ashardalon (a moniker they have heard applied to him in other texts, but also to a draconic ally who seems to be wanted by the Talons of Justice);
the people = the elves (Tel'quessir, The People, allthough this is deliberately vague);
His progeny = Imperagon, the Lord of the Iron Fortress, and therefore his gathering an army and murdering smiths;
the blade that was broken = the Blade of Fiery Might (again, vague, as there can be many swords that may be referred to as the Blade that Was Broken);
Lord of Iron = Lord of the Iron Fortress, or Imperagon;
cut a swathe of flame and blood = invade the prime material plane.
So, after my rambling, I hope I helped somewhat.

When I craft prophecies, I basically try to use symbolic language and epithets to refer to otherwise obvious nouns. As for how my players interpret them.... well, basically they don't; they more or less wait to see what happens next :\.