Personally I was just bored one day and looked through the Wikipedia index of weapons. Saw the sling and look at it and then, well you can guess what happened after that. So what about y'all? The Bible? A friend? Video? I'm very interested to know.

the first time i read about slings was accidentaly in an encyclopedia, no images. it was so simple, yet i couldn't understand it.

then a couple of years later saw a sling(david and goliath in documentary with a lot of video editing) i didn't believe this could work. but this time i tried it, thinking it may come to me that way . but failed.
somehow i had discovered slinging.org forums but didn't thought it would help much

maybe a year later a good mix of boredom and curiousity sparked by the need for something convenient to just throw/shoot things lead to the making of a new sling and trying harder
researching in here and youtube videos helped with the first steps

    In a roundabout way acorns got me interested in the sling.  I have always felt a bit out of place in modern society... many of us do.  Take me back 100,000 years and I'd be fine.
    In the Fall here in New Jersey millions of tons of acorns wash down our sewers, totally wasted.  I read that the Native Americans used to process them into flour. I HATE to waste anything so I decided to give acorns a try.  My first attempt failed miserably because I didn't crush the acorns finely enough prior to rinsing them.  You have to rinse them for a couple of days to get all of the tannins out or most kinds of acorns will be inedible.
    Anyway, acorns got me thinking about all things from our hunter/gatherer ancestors which led me to the sling.  As I mentioned on a previous thread, the thing I like the most about the sling is that it's something I can make and use completely by myself, Naked and Afraid style.  I don't need anything whatsoever from modern technology.  Just a little plant fiber, hair, or hide and some round stones, of which we have plenty here. If the modern world was to end today I'd have a sling immediately, with no help from anyone or anything.

Baldurs gate video games. A dress up party and a day alone with a piece of cord. Fast forward 15 months and I carry it everywhere and my friends get sick of me talking about it/ doing it.

something to do while walking the dogs. Sling came after: yo-yo, staff twirling and juggling
Over 30 years ago now.

I actually got into hand slinging by building a model trebuchet. It had a really crappy sling for throwing marbles, so I looked up how to make a better one. I came across making a three strand, knotted sling on a tutorial here, and decided to practice by making a full sized one.

I did end up building a nice (though tiny) woven pouch sling for the trebuchet. Just that improved its distance by about 15%. It also got me into playing around with hand slings.