The Jerusalem artichoke is one of my favorite plants. It looks like a small sunflower and the bulbs/tubers can be eaten. Similar to a potato you can steam the tubers for a sweet nutty taste or you can slice them raw and eat them that way. I have never seem them for sale anywhere but seed catalogs have them.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Sunroot_top.jpg/220px-Sunroot_top.jpg)