F 1 D 0 - 2003 07 10 at -030

Bang.

1. n. Common spoken name for ! (ASCII 0100001), especially when used in
pronouncing a bang path in spoken hackish. In elder days this was considered
a CMUish usage, with MIT and Stanford hackers preferring excl or shriek; but
the spread of Unix has carried 'bang' with it (esp. via the term bang path)
and it is now certainly the most common spoken name for !. Note that it is
used exclusively for non-emphatic written !; one would not say
"Congratulations bang" (except possibly for humorous purposes), but if one
wanted to specify the exact characters 'foo!' one would speak "Eff oh oh
bang". See shriek, ASCII.

2. interj. An exclamation signifying roughly "I have achieved
enlightenment!", or "The dynamite has cleared out my brain!" Often used to
acknowledge that one has perpetrated a thinko immediately after one has been
called on it. 

From a version of the "New Hacker's Dictionary"
http://www.antionline.com/jargon/bang.php