And, some silly ideas:
Wear a sign that says "Got Milk?". Paint a milk mustache over your lip with make-up or other non-toxic white substance.
Wear all gray or all blue. Make a shark fin out of cardboard and attach it to your back.
Just tie a computer CD around your neck and carry a lighter. When someone asks what you are, hold the lighter up to the CD.
Attach a golf ball to a headband and wear it on top of your head.
Magic 8 Ball
Wear all black. Cut a large 8 out of white cloth, cardboard or paper and pin or tape it to your back. When people ask you what you are, tell them "reply hazy, try again," or "cannot predict now." Or tell them to shake you and ask you a question.
Wrap yourself in duct tape so the sticky part is facing out, then roll around on the lawn.
Tic Tac Toe
Attach a pack of Tic Tacs to the tip of your shoe.
Put a picture frame around your neck and sign your shirt.
Wear pink clothes and put a piece of black electrical tape on your forehead (coin slot).
Glue pages from a book onto a black sweatshirt and sweatpants. Add spider webbing to your hair. Voila! Instant internet!
Wear all black, and attach a postage stamp to your chest.
Hotglue some quarters to hairclips, and place in your hair.
Wear an extra-large bra over your clothes. Stuff it with jars of spices.
Man Walking Into a Bar
Get a piece of pipe and attach it to your forehead