This post is courtesy of my mum, who taught me how to do this, and don't worry, its very easy. Cut the sprouted ends off of some sweet potatoes. And stick the cut end in some water. Change the water when it starts looking icky, and make sure it doesn't run out of water, but besides that leave them pretty much alone (a thought just occurred to me that we don't have "city" water, so there is no chlorine in our water...I have no idea if this makes a difference). After a while they will start to look like this (its not required to be near a sink full of dirty dishes), with lots of nice green leaves.