I happen to have a bunch of old sarees laying around in my fabric bin. This worked well because they were already embroidered on the side, and they are super long. Any lightweight fabric will do and you could add your own embellishments (but that might make them more like twenty minute scarves, which is still pretty quick if you ask me).
First I laid the saree flat on the ground and folded over the edge that I wanted to use for my scarf. I folded ten inches over (so that I had a total of 20 inches folded in half) and cut a long strip. For my daughter's scarf I used a strip that was two yards long. For mine I used closer to five yards. The final length of the scarf was slightly more than half of what I started out with.
Next, I hemmed the short edges of the strips (the ends of the scarf). Then I folded the strips back up lengthwise, with the front sides facing in. I experimented a little bit with the tension on my sewing machine. I increased the top tension as much as I could without putting too much stress on the thread. And, I increased the stitch length as high as it could go. This created a gathering stitch.
|This is what it looked like after I sewed the open edges together with a gathering stitch.|
|This is what it looked like after I sewed both sides up and folded it right-side out.|