Every day is Earth Day, hard-core environmentalists will tell you, but on the calendar it's April 22. And if you want to show some support for Mother Earth, you might as well do so without abandoning your techie principles. There's no shortage of energy-efficient, ecofriendly, or generally "green" gadgets available, but here are 15 of the coolest, weirdest, and most practical, in no particular order.

Voltaic Generator

Packing up to 15 watts in its included battery pack, the £499 Voltaic Generator can juice a laptop for roughly 5 hours. Plus, it's made almost entirely of recycled pop bottles. Looking for a more mainstream solar bag? Samsonite plans to release its own line of solar products this summer.

Voltaic Generator

Solar-powered camcorder

A search for green tech on Amazon turned up this 720p, 10X-optical-zoom camcorder fitted with two solar panels. Not a bad deal for $250, but fair warning: It's a no-name brand, and the product has no customer reviews on the site, and we can find it available only in the States. It's a nice concept, at least.

Solar-powered camcorder

NEXT: the coffee-based printer >>

Every day is Earth Day, hard-core environmentalists will tell you, but on the calendar it's April 22. And if you want to show some support for Mother Earth, you might as well do so without abandoning your techie principles. There's no shortage of energy-efficient, ecofriendly, or generally "green" gadgets available, but here are 15 of the coolest, weirdest, and most practical, in no particular order.

Coffee-based printer

Jeon Hwan Ju's RITI Printer, which uses old coffee grounds or tea leaves instead of ink, is one of those gadget concepts that really ought to be actual products. Regular printers are annoying enough as is - I wouldn't mind going green for simple jobs.

RITI Printer

Water-powered alarm clock

It doesn't offer a fancy radio or iPod integration, but the £14 water-powered alarm clock should wake you up and wash away a bit of guilt. Just dump in some H2O, and you're good to go for three months, as the evaporation process powers the clock. Oddly enough, it isn't waterproof on the outside.

Water-powered alarm clock

NEXT: smart strips >>

Every day is Earth Day, hard-core environmentalists will tell you, but on the calendar it's April 22. And if you want to show some support for Mother Earth, you might as well do so without abandoning your techie principles. There's no shortage of energy-efficient, ecofriendly, or generally "green" gadgets available, but here are 15 of the coolest, weirdest, and most practical, in no particular order.

Smart power strips

Some gadgets quietly draw energy even in standby mode, but who can be bothered to unplug everything or to trigger-flip the surge protector just to save a few watts? Bits Limited's Smart Strips, starting at £27, automatically shut off several devices, like Blu-ray players or game consoles, when you turn off a master device, such as a television.

Smart Strips

Personal generator

Enough with the solar-powered gadgets already. The nPower Personal Energy Generator builds up charge as you move--just throw it in a bag or hold it in your hand. It's compatible with plenty of gadgets, including iPhones and BlackBerry handsets. The maker, Tremont Electric, is taking preorders now.

nPower Personal Energy Generator

NEXT: HYmini Wind Charger >>

Every day is Earth Day, hard-core environmentalists will tell you, but on the calendar it's April 22. And if you want to show some support for Mother Earth, you might as well do so without abandoning your techie principles. There's no shortage of energy-efficient, ecofriendly, or generally "green" gadgets available, but here are 15 of the coolest, weirdest, and most practical, in no particular order.

HYmini Wind Charger

The HYmini stores energy to its internal battery, which can charge MP3 players, digital cameras, and other 5V devices. Particularly cool are the optional arm band and bicycle holder; you may look a little silly wearing one of these chargers, but think of all the juice you'll generate.

http://www.hymini.com/html/HYmini.html

PowerPlus Leopard

If you're the kind of couch potato who would rather stick with one channel than get up to change the remote's dead batteries, you'll appreciate the £9 PowerPlus Leopard. Its small solar charger can even absorb ambient light, so you needn't place it in direct sunlight to juice up.

PowerPlus Leopard

NEXT: EcoCube speakers >>

Every day is Earth Day, hard-core environmentalists will tell you, but on the calendar it's April 22. And if you want to show some support for Mother Earth, you might as well do so without abandoning your techie principles. There's no shortage of energy-efficient, ecofriendly, or generally "green" gadgets available, but here are 15 of the coolest, weirdest, and most practical, in no particular order.

EcoCube speakers

You won't find a fancy power source for the $15 EcoCube speakers - they actually draw charge from whatever device you connect to them - but they are made entirely of recycled materials. Best of all, they fold completely flat for maximum portability.

EcoCube

HydroRight Toilet Water Saver

A single flush of the toilet uses up to 1.6 gallons of water, but installing the HydroRight Toilet Water Saver lets you flush away less. Two buttons on the device allow you to perform either a small flush for regular business or a full send-off for, um, big jobs.

HydroRight Toilet Water Saver

NEXT: soy-based printer >>

Every day is Earth Day, hard-core environmentalists will tell you, but on the calendar it's April 22. And if you want to show some support for Mother Earth, you might as well do so without abandoning your techie principles. There's no shortage of energy-efficient, ecofriendly, or generally "green" gadgets available, but here are 15 of the coolest, weirdest, and most practical, in no particular order.

Soy Ink

So your office printer is out of toner. Now's the time to push for some soy ink as a replacement for regular, oil-based toner. SoyPrint, which sells the "green" (but actually black) ink, will even send you sustainability reports so that you can feel good about the purchase.

Soy Ink

Battery Wizard for Alkalines

It's common knowledge that if you try recharging alkaline batteries, they'll leak corrosive material or explode. The £16 Battery Wizard instead reconditions such batteries to make full use of the chemicals inside. Using the contraption for AAA, AA, C, or D batteries reportedly extends their life by ten times or more.

Battery Wizard

NEXT: an iPhone case with a difference >>

Every day is Earth Day, hard-core environmentalists will tell you, but on the calendar it's April 22. And if you want to show some support for Mother Earth, you might as well do so without abandoning your techie principles. There's no shortage of energy-efficient, ecofriendly, or generally "green" gadgets available, but here are 15 of the coolest, weirdest, and most practical, in no particular order.

NovoThink Surge cases

It seems as if every iPhone owner has a case to protect their precious device, but NovoThink Surge cases actually put the extra layer to use, gathering charge with a solar panel. You even get an app that lets you plan your solar needs based on how you use the phone.

NovoThink Surge cases

Cyber-Rain Sprinkler Controller

Cyber-Rain may sound like a sweet name for a video game, but it's actually a way for automatic-sprinkler owners to save water. The controller coordinates with a networked PC to check local forecasts, and adjusts sprinkler schedules based on precipitation, humidity, and temperature. How long the $400 device will take to pay for itself probably depends on the size of your yard.

Cyber-Rain

NEXT: the energy detective >>

Every day is Earth Day, hard-core environmentalists will tell you, but on the calendar it's April 22. And if you want to show some support for Mother Earth, you might as well do so without abandoning your techie principles. There's no shortage of energy-efficient, ecofriendly, or generally "green" gadgets available, but here are 15 of the coolest, weirdest, and most practical, in no particular order.

The Energy Detective

What good is all this energy-saving gear if you can't measure how much of a difference it makes? The Energy Detective connects to your breaker panel and transfers data to a wireless transmitter connected to a wall outlet, which then sends the information to the gadgets pictured here. TED also connects with Google PowerMeter, a free web app for tracking home energy use.

The Energy Detective