I had looked all over for a good pattern but the only one I found looked more like a wizard robe than a Jedi robe. I also found a sort of Dracula robe pattern, but it looked pretty hard (I am not that great of a seamstress). Google to the rescue! After searching a ton of different websites, I found some easy(and full of the awesome) instructions HERE.
I did things a little differently than they described, namely folding the material in half again so that I got things pretty symmetrical. I also fashioned a pattern out of some tissue paper so that I have something to go by for future robe making. Z wasn't home to trace so I used my smaller son as a model. The only supplies used were 3 yards of brown cotton fabric, brown thread, and 2 sheets of tissue paper for my "pattern".
Here are some pictures:
First I folded the fabric so that the neck is on a fold and then folded again so that the middle is on a fold. Then pinned on the pattern. (I got scared at the last second that this would be too small so moved the pattern down and over to the right a little)
Haha here is my sad attempt to show where you sew up the sides and hem the rough edges. After sewing up the sides, turn it right side out so that your seams are on the inside of the robe. Then hem the rough edges and cut the front for the robe opening and hem those sides up too.