In the latest issue of Scientific American, Michael "The Skeptic" Shermer looks at how the human brain is a "pattern-recognition machine" that can make interesting mistakes. From the column:
Consider a few cases of false pattern recognition… the face of the Virgin Mary on a grilled cheese sandwich; the face of Jesus on an oyster shell (resembles Charles Manson, I think); the hit NBC television series Medium, in which Patricia Arquette plays psychic Allison Dubois, whose occasional thoughts and dreams seem connected to real-world crimes; the film White Noise, in which Michael Keaton's character believes he is receiving messages from his dead wife through tape recorders and other electronic devices in what is called EVP, or Electronic Voice Phenomenon. EVP is another version of what I call TMODMP, the Turn Me On, Dead Man Phenomenon–if you scan enough noise, you will eventually find a signal, whether it is there or not.
Link (Thanks, Gil Kaufman!)