An anonymous reader writes "These folks at Public Lab have published instructions to hack a conventional camera to do photosynthesis photography, just like NASA's LANDSAT satellite. What better way to introduce your kids to space technologies and learn more about the environment? Measure the health of your garden, all with a simple filter switch and some post-processing. It's thoroughly documented at http://publiclab.org/wiki/near-infrared-camera, and you can do it to a variety of cameras."
(And here's a link to the related — and fully funded — kickstarter project