You can fix fraying wires, hang pictures (without a nail), create ergonomic grips on tools, and soooooo much more.
It sets strong because it turns into silicone rubber, permanently bonding to almost any surface. It’s waterproof (use it to secure a shower caddy!), heat- and cold-resistant (use it to insulate a pot handle!), and electricity-insulating (fix those constantly fraying smartphone cords!).
Promising review: “I’ve used Sugru for years and can testify to its durability and versatility. Probably the longest term repair is the perch on a birdfeeder. It has been hanging outdoors 365/year for 5 years now in rain snow and heat, and still holding up. I’ve also used it to repair a favorite silicone cooking spoon, all sorts of cord management, bathroom “caulk”, sunglasses repair, lamp repair, and more I can’t think of at the moment. I few times I’ve needed to remove it, and thats easy too. (I don’t really understand a product with such good adherence can also be so easy to remove, but ther you have it!) Plan your usage carefully, because once you open the packet you might as well use the whole thing up. No matter how tightly I’ve re-wrapped it, it always becomes unusable within a few days.” —Big Shopper
Although the reviewer above notes that once opened, the leftover product hardens in a few days, many reviewers note that it stays usable if you keep it in the fridge!
Get an eight-pack from Amazon for $19.99 (available in seven color sets).