Sens-O-Tape was a method of recording that was used by the Magratheans. It allowed the user to become completely immersed in the event they were experiencing with all of the senses, hence the name. A Sens-O-Tape recording was made of the time when Deep Thought was created, and when it revealed the Ultimate Answer to the Ultimate Question of Life, the Universe, and Everything which was shown to Arthur by Slartibartfast.
There was also a Sens-O-Tape catalogue of the planets that Magrathea had created, including a planet made from solid gold, a planet knee-deep in fish, a gloomy planet, and a planet with a meadow full of cows. Zaphod Beeblebrox, Trillian, and Ford Prefect were put in this catalogue by the Magratheans to keep them busy while they were discussing what to do with the three.