OK folks, strap yourselves in. This is a good one.
So, an astrologer has cast a horoscope for Randi and found he makes a good skeptic.
I know, this sort of thing has a potential for causing a catastrophic collapse of the space-irony continuum, but, assuming this is not satire, then prepare yourself for what must be the absolute, 100%, guaranteed rock-solid most ridiculous thing ever to have been attempted ever in the history of our Universe or any other.
A synopsis can be found here, too. But you might want to keep all sharp objects far away, and anything that might shatter when you start screaming.
Anyway, his basic synopsis is that Randi makes a good skeptic. Shocker, eh? So you see the problem: the astrologer knows about Randi, so he's actually predicting nothing! He researches Randi before casting the horoscope, and then lo! Astrology predicted everything he found!
Now, Randi has a rebuttal:
The horoscope part starts about 5 minutes in.
That's when things get really weird: turns out, the astrologer was using the wrong birthdate for Randi! He was off by 20 days and an entire sun sign. So Randi gave him the actual birthdate, and the astrologer recast the horoscope with the new date and new sign. And guess what? Go on, guess.
He predicts Randi makes a good skeptic!
Amazing (so to speak). Is that what you guessed? Astrology must be more powerful than I thought. All you have to do is already know everything about a person, and then make your conclusions. My obvious mistake was putting all that emphasis on the whole "pre" part of the word "prediction". I suppose it's not so hard to make a prediction after the fact.
So, what have we learned here? Like the astrologer, we haven't learned anything we didn't already know. But maybe we do have more evidence for one thing...