Alternatively you can take the top from a pineapple - as long as the growing middle has not been removed - strip the lower leaves from the stalk and leave it to dry on a windowsill for a couple of weeks. You will see the little vestigial roots in the leaf joints.
After about 8 months or so green shoots will appear from this root, and these are broken off and planted out under glass and left to grow for up to 2 years! One of the most startling things I learned is that they are not given any nutrients or feed, they are grown in woodchippings and sawdust, with a top dressing of pittosporum leaves!
Now this is the bit where I come unstuck in London - the temperatures inside these greenhouses are unbearably hot! Just about the same temperature as a very hot sauna or Turkish bath.
In fact this picture above had to be taken quickly within about half a second of walking inside the greenhouse as my glasses and camera lens were completely steamed up. This is a baby pineapple, the beautiful flowers bloom out of each of the tiny segments - I did not know this!