I became interested in spinning wool into yarn fairly recently. Beth started learning how to spin on a drop spindle. She tried to get me interested, but I just wasn't. However, we did go to a spinning guild open house meeting where I looked at some of the spinning wheels, and saw how they worked.
Spinning wheels are a really interesting invention. They're actually relatively recent, considering the history of spinning. What we recognize today as a spinning wheel was developed some time in the 1800s. (What Sleeping Beauty pricked her finger on would today be called a Great Wheel or a Wool Wheel, which is really an improved spindle, and not very related to what we think of as spinning wheels.) Modern spinning wheels combine the mechanism for twisting the wool and for winding it onto a bobbin so that they're accomplished at the same time, rather than as two very distinct steps, and works well at high speeds with leather, bear grease, and parts which are not very precisely machined.
I became fascinated by the construction of spinning wheels and started designing my own. Beth wanted to make her own spinning wheel as well, and so we enlisted the help of Beth's father, who's good at design and has a wood working shop in his garage. The three of us first built a modern-style upright bobbin-driven spinning wheel for Beth. Now that we had constructed a spinning wheel, I was interested in using it, and when Beth wasn't using her wheel I practiced on it.
Since spinning is the sort of activity — like knitting — that's most pleasant to do in the company of other people doing the same thing, it was obvious that we needed a second spinning wheel. So I set about designing a bench-type flyer-driven spinning wheel for myself. On a trip out to my father-in-law's (when Beth was attending a baby shower for her cousin), he and I built and assembled the bench, flywheel, and most of the structure for supporting the flyer and bobbin (technically, it's called the mother-of-all and the maidens). I brought it home, where I built the flyer, assembled the bobbin, and built the treadle. Then the real work started: I spent weeks sanding, staining, and finishing the wheel. Finishing wood is an astoundingly long and painstaking process — especially if you have to do the sanding without the aid of power tools — but it does produce really beautiful results. Someone who saw the wheel even paid me the compliment of assuming that I bought it!