/*
 * God only knows what the original author
 * wanted this undocumented feature to
 * do.
 *   %5++ is really r7
 */

Source: Direct link to the source code
Programming language: C

# Now: we need to create a key for our encryption, but,
# ther’s a “but”, if we simply put a clear text string in our
# .pyc module, anyone can simply recover the key with a
# strings of the pyc. So, we do another dirty trick: we use
# only unprintable chars!
# Note: F*cking hell, this is a *VERY* bad coding! oh my god
# what i’m doing

Source: Direct link to the source code
Software: astronomix
Programming language: Python

/*
 * Unfortunately it looks like we’re f*cked either way: some
 * scripts fail if you don’t propagate the query string, some
 * fail if you do… God, don’t you just love it when people
 * can’t read a spec? Anway, since we can’t get it right for
 * all scripts we opt to follow the spec.
 */

Source: Direct link to the source code
Software: HTTPClient
Programming language: Java

/***********************************************************
* And so I saw the wicked buried, who had come and gone from
* the place of the holy, and they were forgotten in the city
* where they had so done: this is also vanity. (Eccl 8:10)
*/

Source: Direct link to the source code
Package / Software: Sun Solaris
Programming language: C

Der große Knall im Jahr 2000 blieb aus, die kleinen Knaller findet man in Quellcode Kommentaren :-)

// Yes, isn’t it lovely to have to deal with f**king dates
// that only have two digits?
// “Hi, I’m the guy who designed the packet format.
// I didn’t think we’d ever reach the year 2000, so
// I didn’t figure we’d ever need 4 digit years.”
// I hope to god he DIDN’T make it to the year 2000.

Source: Direct link to the source code