Apollo 17's rover lost a fender extension and threw a rooster-tail of abrasive dust over the crew and instruments, so Houston designed a replacement out of four laminated maps and duct tape overnight.

It was clamped on with two lamp clamps from the lunar module. Without it the dust would have coated the radiators and cooked the electronics before the third moonwalk. The improvised fender is now in the Smithsonian, and it is the best surviving example of how much of Apollo ran on things people worked out that morning.