|I was given a wool skirt a few years ago that I had since sort of thrown in the closet and forgotten about until I wore it yesterday. It has a really nifty detail I thought worth sharing.
The skirt is lined and faced (no waistband), and one side seam has a separating zipper inserted the entire length from hem to waist. The zipper is set in upside down, so you can unzip from the hem as far as you like for an adjustable side-slit. It's a fairly basic, conservative skirt otherwise--straight and knee-length, with an invisible zip at CB. The side-seam zipper, on the other hand, is the kind you'd find in outerwear, heavier-weight with big plastic teeth. The seam itself is faced, with the zipper sandwiched between facing and skirt and edge-stitched down. The facing extends about an inch on either side of the zipper on the interior before attaching to the lining.
It's a fun look overall, and should be easy to copy (not that I've done so, of course ;)