Like an orange flag to a field?

Leonardo da Vinci once said that simplicity is the ultimate sophistication, and today's great idea is - if anything - simple.

The Ag Flag is a flag on a flexible pole, with a bit of paper on the end. You bend the flag to the ground, stick the piece of paper to a stake in the ground, and when the ground gets wet, TWANG, the paper dissolves, the flag pops up, and you know you've done your irrigating.

If your back yard is less than 20 acres, this might not be for you. But if you need to know whether your watering is done from over a mile away, this could be the easiest way to tell.

I wonder if the Ag Flag's inventor, Mike Hansen, got the idea from the Australian barometer, on the right?

The Ag Flag is currently the top vote getter among the Top-10 New Products for the World Ag Expo 2011, to be held next month in Tulare, California.

Here it is in action: