There is a story in the icelandic saga´s (oldest prose in europe) where a man defends his homestead against a large number of attackers (of course some kind of feud going on) using a sling with great skill. His faith is sealed when his evil wife (also a recurring theme in the saga´s, could have something to do with the fact that it was catholic monks who actually wrote them down) refuses to give him a lock of her long hair to repair his sling when one of the strings  breaks.
I could find out which of the saga´s this is, the name of the guy, icelandic word for sling and so on.

Yes,please elaborate.

hmm, makes you wonder if human hair was used regularly for slings.

Well, hair could be woven. It was used to make the ropes for torsion catapults, so I see noreason why it wouldn't work.

I believe we have a record of some human hair slings from Polynesia.

Evil wife? :o  

I'm asking my girlfriend for some hair! ;D

I heard that it was for use as a bowstring instead of a sling.

And the wife brings up the fact that she was refusing because at some earlier time he had mistreated her (struck her, I believe).

I can't really see human hair doing well as a bowstring, but that's how I heard the story.

For making slings, human hair is strong enough.

Ehhm, sorry to say Kcrandal is right; my sling obsession muddled my memory somewhat :-[.
Well anyway, he was called Gunnar from Hliðarenda, and history has it he was a good fighter and archer, his melee weapon of choice was an"atgeiri" a halibard/pole-arm kind of weapon.
The story is a bit strange from a tactical point of view, I mean getting into such close combat that your bow string is cut by a swordstip, and still having time to argue with your wife about repair materials strikes me as a bit odd. Well there was a doorway involved so who knows? Still have the feeling his pole arm might have served him better under the circumstances.

About his wife Hallgerða, she was at the time not regarded as evil on ground of her refusal to help her husband. Gunnar had some time earlier declined to support his wife in a matter of honour; this loss of honour was regarded (literally) as a matter of life and death. Making her actions a justifiable revenge....

The icelandic word for sling is valslöngu, or slönguvalur, depending on who you ask... ;)