The Omnificent English Dictionary in Limerick Form is a project to write a definitional limerick for every single word in the Oxford English Dictionary.
artery
The arteries carry the blood;
Without them our bodies would flood.
They're elasticized – sorta;
The chief's the aorta.
If it ruptures, that's all for you, Bud!
(Thanks, Philip!)
Update: Chris J Strolin, Editor in Chief of the OEDILF sez, "We are in the process of writing limericks for every definition of every word in the English language, NOT just those in the Oxford English Dictionary. That *was* our original goal but the OED lawyers weren't happy with the idea and so, since then, we've tried to maintain a respectful distance."