(Added NOTE: I only glossed over the steps here. I am assuming you have at least beginning to intermediate sewing skills. You need to know how to make gathers and sew a seam.)
I've been wanting to try a fashion recycling project with old t-shirt material. The upside is that it doesn't unravel and doesn't require hemming. It's also light and great for spring or layering.
I took a comfy tank top and an old long sleeved t-shirt, and ended up with this. It has an airy Anthropologie feel to it, don't you think? I used this tutorial from Sachiko at Tea Rose Home almost step by step. She has more in-depth photos, but I wanted to share my project photos with you, too.
6. Sew 1/2" from one edge of the rectangle using your biggest stitch size. Pull one thread to make it ruffle. Center it on the front center of the shirt. Sew each additional ruffle under the first. I made the top ruffle overlap the next one by about 1 1/2" to hide the stitching.