Definitions for gang bang
A gang rape.
An orgy, especially a sexual one.
A gang fight.
Protecting gang turf, especially when dealing drugs or other black market objects.
The New Hacker's Dictionary
The use of large numbers of loosely coupled programmers in an attempt to wedge a great many features into a product in a short time. Though there have been memorable gang bangs (e.g., that over-the-weekend assembler port mentioned in Steven Levy's Hackers), and large numbers of loosely-coupled programmers operating in bazaar mode can do very useful work when they're not on a deadline, most are perpetrated by large companies trying to meet unrealistic deadlines; the inevitable result is enormous buggy masses of code entirely lacking in orthogonality. When market-driven managers make a list of all the features the competition has and assign one programmer to implement each, the probability of maintaining a coherent (or even functional) design goes to epsilon. See also firefighting, Mongolian Hordes technique, Conway's Law.