March 29, 2008, was an especially dark night for some people. Notable landmarks like Alcatraz Prison, the Sears Tower and the Sydney Opera House all went dark for an entire hour. This wasn't some strange coincidental power outage, though. Around the globe -- from Tel Aviv to Times Square -- people voluntarily switched off their lights to symbolize their growing concern about global warming. This show of unity, now an official movement called Earth Hour, is one of the more mainstream ideas to lessen our impact on the environment; others are decidedly more off the wall.

Energy Production Pictures

Earth Hour
Mark Kolbe/Getty Images
This hot air balloon promoted Earth Hour in Sydney, Australia, days before the worldwide event. People switched off their lights for an hour to spread the word about climate change. See more energy production pictures.

But drastic times call for drastic measures, and many people would categorize the current state of ­the environment as such a time. We live on a planet of finite resources -- some of which are crucial to our survival and others that harm the environment every time we use them.

Up Next

­Rather than wait for the oil wells to run dry and the ozone layer to become nonexistent, many people are looking ahead to cleaner alternative sources of energy. Some of these, like solar power, hybrid-electric vehicles and small, hand-powe­red gadgets are already catching on. Others, however, like feces-fueled water heaters, may take a little getting used to.

­Here, for your reading enjo­yment, are five of the wackier ideas for alternative energy. Some of them are already available for the more environmentally savvy among us; others may need a few more trial runs before they catch on. Either way, if you're reading this during a self-imposed Earth Hour, round up your hand-cranked flashlight and prepare to be surprised -- or even amused.