When you're thinking about who to be for Halloween why not skip the good guy and be a villain. Sometimes it can be more fun that way. One colorful villain to consider is Jafar from the movie Aladdin. If your friends have an Arabian-themed party you can be Jafar and revel in how evil you look.
Find a dark dressing gown. Black is the best since that's what Jafar wore in the movie, but a navy or midnight blue could work as well. Tie a red ribbon around the middle of the body. Velvet pants underneath will complete the outer part of the costume.
Make a cape from a dark red piece of material or a bed sheet. Use safety pins to attach the cape to the dressing gown. You can also sew it on if you are going to keep this as a permanent costume.
Wrap a dark colored towel around your head to make the turban. It should be the same color as the dressing gown. Fold it in tight and secure it with a safety pin it to keep it from unfolding.
Make a jewel by cutting a piece of cardboard in a jewel shape and covering it with red colored foil. Safety pin this to the towel. You can also use costume jewelry that is the color you want and pin that on instead but the jewelry piece should be large enough to be seen.
Attach a rubber snake to a walking staff with some tape. Use tape colored the same as the staff and snake so it blends in well. It is important to make this look good since it was the source of Jafar's power.