A friend of mine keeps making really bad puns. There is another punster at my office, too. He knew the Big Word for punning:
parÂ·oÂ·noÂ·maÂ·sia [par-uh-noh-mey-zhuh, -zhee-uh, -zee-uh]
1. the use of a word in different senses or the use of words similar in sound to achieve a specific effect, as humor or a dual meaning; punning.
2. a pun.
paronomasia. Dictionary.com. Dictionary.com Unabridged (v 1.1). Random House, Inc. http://dictionary.reference.com/browse/paronomasia (accessed: April 18, 2007).