I swear this carrot wasn't the result of radioactive levels in the soil or something (chuckles nervously). But really, I grew this little guy as a bit of an experiment. I'm sure every kid has rammed a couple of toothpicks into a potato, stuck it in a glass full of water, and watched roots and leaves grow from it as a sort of science experiment. Well, the principle works really well with carrots, too (among other veggies, but I'll get back to that).
After you've chopped off the top of a carrot for your dinner, instead of discarding it, you can place it in a shallow tray of water. Provided you change the water everyday to prevent it from turning to mush in its own decaying pool of carrot-flesh-eating bacteria, it will develop thin roots and regrow its leaves. After the roots form, replant it into some healthy soil, keep it well watered and watch your carrot top grow. It may or may not turn into a tangled mass of deformed fleshy roots...it may only grow single taproot, or it may not even produce anything but a bushy set of parsley-like leaves. But it's a cool way to use something that would have been thrown away without a second thought.
I left mine in the ground for too long, and the pill bugs got to it before I could. This is the second time they've gotten into my carrots, and so I'll have to keep an out for them if I ever want the chance to make my own home grown carrot cake.