Added Feb 18, 2013
A top and a dress made from Butterick 5815. Sleeves like these have been called butterfly, batwing, or petal (which I think is more like it due to the overlap of the ends, leaving an opening along the arms).
Both were fairly simple to sew. I substantially took in the front and back while sewing my first version in a top and applied those modifications to my second version in a silk dress.
I stretched out my arms to the tune to R. Kelly’s “I Believe I Can Fly” and Stevie Nick’s “Stand Back” as a reminder to stand back when you are next to somebody with big sleeves ready to wave her arms.
Top: cotton woven with “tape-measure” print
Dress: a Nicole Miller silk with a New Orleans themed print, more like a Mardi Gras celebration.