At the beginning Sherlock calls the new talking car alarms a modern day "pet rock". Pet Rocks were a bizarre fad back in mid 1970's when an entrepreneur, tired of listening to people complain about their pets, decided the best pet would be a rock. He collected small stones and painted them, and sold them complete with a care guide. The Pet Rocks became an almost immediate best seller, and made their creator a millionaire as a result. The fad died out within a year.
On Sherlock's desk is a copy of Stephenie Meyer's book New Moon from Twilight.