[GregBuchholz]

I don't know if it counts as unusual, but I want a robotic gardener that identifies weeds and zaps them with a laser (or otherwise kills them).

https://www.google.com/#q=infrared+plant+identification

...and it seems like there could be quite a sizable market for such a device that automatically helps grow your food.

[airbreather]

Broad scale agriculture already uses similar technology to selectively identify and spray weeds in grain fields.