I got this interesting shirt with a portrait of central park from the thrift store. I liked it as a shirt and will wear it as both, but here is an easy DIY to sew stretch shirts into a skirt/tube dress.
If you like it as a shirt too, you can also just tie the arms around your waist and it becomes a convertible shirt/skirt.
Because it was stretchy, all I did was sew it into a tube...similar to this pencil skirt refashion (here) but without the zipper and waist band. Turn inside out and pin it to fit. Sew. Trim excess fabric and sleeves.
Even can be worn as a tube top or dress...