I normally sew for myself, having had a couple of really awful experiences when asked to sew something (a chiffon dressing table cover springs to mind). But when my friend told me the cost of a skirt to wear while she rode her horse side-saddle, I leapt in and offered to make one! Luckily she had a 'practice' skirt which I borrowed to make a toile. It's a very strange garment, having no back to the skirt and a weird massive curved side.
Here she is wearing the lovely skirt (jacket model's own!). It was a challenge, but one I enjoyed.
What's the strangest thing you've sewn?