For the next few weeks I'll dedicate some time to finding electronic costume projects to inspire you to make something playful and interactive this year. I myself will be helping a friend make a cool costume which I will post later.
I discovered the spinning feather hat on Flicker user's marrije feed. There is something so "sprightly" about this spinning feather cap that I feel will translate beautifully into an esoteric costume. You really don't need an arduino for the set-up so you can do it on the cheap if you wish (unless you plan on incorporating sensors of course).
Also I'd love it if you guys would help me out and post any other inspirations you stumble upon on your blog. I'll make sure it shows up on the homepage.