For the 500th show, Steve Caplin takes a look back at some of the highlights of 10 years of Gadgets & Gizmos. He covers sprayable sleep, cows imitating zebras to ward off mosquitoes, crows collecting cigarette butts, NFTs, self-parking slippers, KFC chicken-tasting nail polish, the first human head transplant, the Skunklock noxious bike lock, Refrigerdating, the robot dog flamethrower, ant populated gin and how to make pain relief pills 10 times more effective.