I love doing it. They are never clear, but they are usually scary. Here's one I gave them in an email between sessions a month or so ago:
That night, you dream...
As you drift off to sleep, you are sucked into a void, one lacking light, sound, or emotion. In a burst of light, you appear...somewhere. There is a tiny round glowing entity, both home and source of all that you are, yet despising you for all that you are, which lies beneath you. Slowly, your vision clears, and you begin to recognize shapes, ideas pour into your mind. You know your truest identity, in this world and the ones to come. Behind you, sensed more than seen, sit the powers of the world, their backs turned to you as they contemplate a greater game which you cannot comprehend. Yet is is played on the same chessboard. While of the world, they are not begotten of the world as are you. Slowly, the vision clears, and beneath you is a circle, no larger than a marble, which slowly comes into focus and grows larger. Behind you, powerful forces urge you this way and that. You can almost feel strings attached to your limbs, needles pushed into your back, trying to force you in different directions, pulling you from your moors on the plan of existence you hail from. Which, when viewed from your new perspective, seems miniscule in the grand scope of the universe. For you feel the scope, once, for a brief instant, and then it is gone. And then it is distant. And then it is but memory in a fog. The world beneath you flashes into being, and you recognize it as your own. You see the land of your homeworld, formerly glorious and immense, now insignificant in the grand scheme of things, much like yourselves. But you sense your own potential. You look down upon the world, in all its magnificence, and feel utter potential, both within and without. And power, the taste of it, intoxicating. Delicious. Godlike you may be, standing there with your golden skull, your demon-corrupted stave pieces. For all of you are there. The Demon-clawed Stavemaster. The Lord of Light and Fellowship, clutching his pommel. The Spawn of Man and Demon, black glowing skull polluting the light with its corruption, stamping out all bonds of unity and fellowship wherever it glows, in perpetual war with all of creation. The Lord of Dogs, Jackals, Wolves and Hyenas, sitting upon his throne, revered as a god. And lastly, you sense more than feel the last Stavemaster, who site in inky blackness of the depths of the sea, waiting, always waiting, to bring back the foulest of entities, who slumbers. Biding his time and waiting. You are joined together, all floating above the BEING which is your world, by bands and shackles of destiny, joined by those who would be your adversaries, friends, lovers, murderers and victims, in a never-ending stream of souls, and yet you sense that you are mere energy for the beings behind you. Morsels of food, nothing more. Linked together by past and future bonds, outside of life and death. Others watch. Contenders without number. The Leftclawed one, craving wholeness of body and soul, craving the desire and passion torn from him by the betrayer of his blood. The Undying one, whose body decays, seeking everlasting life, and everlasting power, in this world and the next. And finally, you are all linked to the plane you were born to, which seems to be the greatest entity amongst you. She/it/he/they? have sent forth forces to oppose all who would despoil its purity, take its energy, as it? evolves beyond its current destiny. It? first acted in the deepest recesses of time amongst the beasts for that era, against beings from beyond space and time, and now in this era, it? acts in the slightest most innocuous of ways. Who will win? The beings behind you care not, as long as you feed them. The great source of life beneath you cares not, viewing you as plants view a plague of locusts. The being beneath the sea who sleeps his endless slumber of madness, it cares least of all, as it mends, mends, awaiting its resurrection to consume that upon which it lives. As you all strive for more.
The Sword-wielder speaks to your mind, looks at your group, and says "Join me brothers, stamp out the darkness. Proclaim yourselves followers of the lords of light, compassion, goodness, and fellowship." And you see his gods, their names burned into your memories, yet unutterable in this place, lest you draw their attention. And then he is gone, sucked back into the ether below. It cost him, that utterance.
The Demonic skullwielder laughs and winks at you, knowingly, and descends to join battle.
The hollow voice of undeath turns in your direction, exhales dust, then looks left, seeing something else, ever seeking.
The jackal-headed does not deign to contemplate such insignificance as yourselves, and returns to more pleasureful dreams, the least understanding of his own potential.
The fires of hate burn steadily your way from the leftclawed, as he slowly sinks down into the bonds of magic.