Laffy Taffy is Willy Wonka's favorite taffy. It is available in fruit flavors and each wrapper comes with a corny kid's joke. For example, "What do you call a cow with no legs? - Ground Beef." Another might be "What's an owl's favorite subject? -- " owlgebra"
Laffy Taffy is a brand of candy first produced in the 1970's. The name refers to both the texture (taffy) and silliness (each wrapper has a joke). The jokes are usually sent in by children who are credited on the wrapper.