Case modding
Case modification, commonly referred to as case modding, is the modification of a computer case or a video game console chassis. Modifying a computer case in any non-standard way is considered a case mod. Modding is done, particularly by hardware enthusiasts, to show off a computer's apparent power by showing off the internal hardware, and also to make it look aesthetically pleasing to the owner.
Cases may also be modified to improve a computer's performance; this is usually associated with cooling and involves changes to components as well as the case.
History
When personal computers first became available to the public, the majority were produced in simple, beige-colored cases. This design is sometimes referred to be as a beige box. Although this met the purpose of containing the components of the personal computer, many users considered their computers as "tacky" or "dull", and some began modifying their existing chassis, or building their own from scratch. One of the original case mods is the "Macquarium", which consists of replacing the CRT screen in a Compact Macintosh case with a fishbowl.