It's April Fools Day in the US, or as I like to call it "liars day". We celebrate all day.Every now and then a program comes along that is so insanely useful and changes how you use your phone that you just have to admire the beauty of it. Solar Charger is one such program.

Using the technology already included in 80% of Android smartphones, Solar Charger turns your electrostatic-sensitive touchscreen into a power source using the photovoltaic effect and our good buddy the sun.

Simply turn it on, place in direct lighting, and the software does the rest. Approaching five million downloads and 9,000+ reviews (most five stars), Solar Charger is clearly quite popular and is destined to be the number one Android application soon, especially on a day like this.

Innovations like this make me worry a bit for our extended battery manufacturers friends at Seidio, but I guess since it doesn't work at night they're not going to have too much to worry about.

Solar Charger is free, contains no advertising, and can save you a buck or two in electricity; however, do be warned that a cloud or an errant cat could always block the juice-giving rays of the sun. And when the battery is low, the efficiency drops through the floor.

Download: Google Play