[nadam]

Obfuscation alone is not interesting, but 'code compression' (to achieve something using as few characters as possible) is a very interesting puzzle for the brain I think.

[pavel_lishin]

It's called "code golf", and from what I can tell, perl is the undisputed king of golfing languages.

Someone ought to make a quiz page - "is this perl golf, or a cat walking on a keyboard".

[apgwoz]

,[.,] is /bin/cat in brainfuck. Though, brainfuck fails miserably at most golfing challenges.

[icebraining]

,[.,] doesn't actually concatenate files, though.

Personally, I think that using golf handicapped languages is the only way to keep it interesting. If you can choose the language, it gets too easy. One could even implement 'cat' as a single character, provided his language of choice.