Science & TechFact
The most famous computer bug was an actual moth.
On September 9, 1947, technicians on the Harvard Mark II found a moth in a relay, taped it into the logbook and wrote: "First actual case of bug being found." The note came from Grace Hopper's team. The word "bug" for technical faults was older, though; Edison already used it in the 1870s.
Useful: The logbook with the moth now sits in the Smithsonian in Washington.
Source: en.wikipedia.org