It's hard to know which category to place this one in -- it's a little bit ESP, a little bit fortune telling, and a whole lot of pseudoscience.
The Global Consciousness Project apparently is trying to use random number generators to detect changes in the the "global consciousness" of the population of the planet. They claim that, when a big event happens, such as the funeral of Princess Diana, the 9/11 terrorist attacks, or the December 26 tsunami, that they observe changes in the pattern of randomly generated zeros and ones.
In the original Star Wars, Obi Wan Kenobi felt a great disturbance in the Force -- these guys claim to be doing so in real life. Better yet, they claim to be doing so before the event happens. For example, they claim that the pattern of numbers generated changed before the first of the 9/11 attacks, as well as before the tsunami hit.
Anyone else suspect they know what's going on here? Various scientists claim to be baffled, so maybe I can help them out. Here's what's probably happening -- humans are being human. You see a spike in the numbers, you scan the news headlines to look for some big event. If you find something, then you can say that the spike you saw detected it. If you don't see anything, wait a bit and check again. Then when you find something, you can say that the spike you saw predicted it. From the other direction, if something big happens in the news, go back and look at your numbers. If you see a spike, bravo! If you don't, look farther back in time. Found one? It was a prediction! (Oh, and if you don't find a spike in the numbers, but instead find a trough, that's okay -- that counts, too.) Didn't find anything at the time of the event or before the event? Don't give up yet! Try looking after the event -- it probably had some sort of psychic impact on the population of the planet for some time after the fact.
Finally, if you weren't able to find a correlation before, during, or after the event, just chalk it up as "one of those things" -- no need to consider it as evidence against the truth of your theory.
The standard of evidence on this appears to be very low. For example, some of the events that their machine "detected" or "predicted" include Mark McGwire's homerun record, the finale of Survivor, and Oprah Winfrey visiting Africa. World-shaking events? Really? Hmm....
So this is the kind of research they're doing at Princeton these days, huh?