I backed this project on kickstarter today, pretty cool you should check it out. 

"Sprout is a pencil with a seed inside. When it's too short to use, it can be planted at home, at the office, or in the classroom." Plant it, pour some water on it—the capsule is water-soluble—and tend it for a couple weeks, and voilà: your pencil stub has metamorphosed into a happy, healthy vegetable or herb.

via Kickstarter