I don't think I've sewn myself anything since I've had kids, but I was inspired by the skirts that Abby made at A Feathered Nest, so I decided to give it a go.
This one has the stretchy cotton waistband--so comfortable and so easy. The instructions come from here.
And this one is even more comfortable. I used sewed 15 rows with elastic thread for this one. I found the instructions by googling "sewing with elastic thread." I found this site and this site helpful.