Think of Sugru as and adult version of Play-Doh or something that every MacGyver type should have in their tool box. Sugru is a type of hackers modeling clay that allows you to fix or improve just about anything. For example you can patch a damaged cell phone, make the ear tabs on a pair of glasses more comfortable, or add some ergonomics to a knife handle. Creativity seems to be the only limiting factor with Sugru. Videos and more information about Sugru after the break.
Sugru is available in different sizes and colors here.