Word play include puns, phonetic mix-ups such as spoonerisms, obscure words and meanings, clever rhetorical excursions, oddly formed sentences, double entendres, and telling character names (such as in the play The Importance of Being Earnest, Ernest being a given name that sounds exactly like the adjective earnest).
Word play is quite common in oral cultures as a method of reinforcing meaning. It is also a cheap way of advertizing 
Word Play