Irene's Spirit [US$1.99, iTunes Link] puts a fortune telling spirit into your iPhone or iPod touch (with the exception of the first generation iPod touch) as long as you're running OS 3.0.
Forget the Magic 8 Ball or Ouija Board. That's kid stuff. Irene doesn't use a 20-sided die or easily pushable planchette to give you an answer. Her answers come from the other side. The other side of what I'm not so sure, but who cares when she is dead accurate. She will make you wonder if ectoplasm will void your warranty.
I had my son ask Irene a question and he totally lost it when she told him the name of his dead grandfather. After two more passes, he got skeptical and figured out what was happening. I should have stopped while I was ahead.
Yes, it's an illusion.
I was very impressed with the best tutorial system I've seen in any app. Being an instructional designer, I know that chunking instruction and requiring feedback periodically is the best way of transferring information. Irene's Spirit is a textbook case of how to get it right.
With a bit of practice, operating the illusion is easy and distracting your audience is helped by lot of vibration noise and weird looking scrolling screens that look like something out of The Matrix.
I thought that it was a well designed, easy to learn trick that will be a hit at birthday parties, but only good for one or maybe two questions before we more skeptical grownups get wind that something's up. I had a good time with it as a casual app, and really think it's worth a look.
Take a look at this video and see Irene in action.