The Mayan Robot Costume

I had half a sheet of Mylar covered styrofoam left over at my work, and I also had a very old computer hanging around -- so in a great blinding flash, Maya the robot was born.
Together we mitred the panels and glued them up with contact cement, added styrofoam eyes, lots of red sparkle paint and then some hand drawn graphics (which were good for a laugh at school).
Her skirt was cardboard strips covered in tinfoil and her leg coverings came courtesy of an automotive windshield sunscreen we found lying on the ground - cut in half and taped together.
Dryer vent tube arms made access impossible without a tilting out head piece, riding on a duct tape hinge. Cooling fans at the back are entirely for show, but still pretty cool.
Finally, we crowned it off with a CPU cooler, two chrome coat-hook antenna ears and a bevy of bicycle lights.
She was very safe and dazzlingly bright that night.
About 20 hours to make and about $20 in bought materials.