Self-heating soup sounds like something from the future: Push a button on the can, and three minutes later the contents are piping hot. But it’s widely available today, along with self-heating coffee and hot chocolate. In Japan, I even found self-heating sake. Pretty high-tech!

Or not. In fact, these products use a chemical reaction known since at least 4000 B.C.—the mixing of quicklime and water. When you roast limestone at about 1,650°F, it converts to quicklime, a powder used to disinfect corpses in war zones. Mix quicklime with water, and it grabs and binds the water molecules, releasing lots of energy in the form of heat. (The material left over, known as hydrated or slaked lime, is the basis of lime mortar, popular in the Roman empire and still used today.)

Soup is OK, but I decided to use the technology to make a self-heating hot tub.

If you want a super-light laptop, you have to pay for it, and you have to use Windows. That’s been the (frustrating) conventional wisdom—at least until late last year, when the Taiwanese company Asus rolled out the Eee PC (pronounced as though it were a single long “e”), a two-pound, seven-inch laptop starting at a mere $300. The tradeoff: It comes with just two to eight gigabytes of flash memory instead of a conventional, larger hard drive, and a simplified Linux operating system that essentially is usable only for e-mail, Web browsing and typing.

No doubt about it; Everex’s gBook computer is a hacker’s dream PC. While we weren't too fond of the company's entry into the ultra-portable market, the gBook sings a different tune: On top of being a fairly well-equipped, full-size VIA-based budget laptop, the gBook also sports some impressive “hidden” features when the hood is lifted and the tires kicked. And while they may not be immediately apparent, in the hands of a seasoned tinkerer the gBook's extras can allow for some inspired modding.

Spring cleaning coming up? Bungees that adjust on the fly and super strong shears make trimming and organizing a breeze. The folks at Toolmonger round up this week's best offerings here.