punster

from WordNet (r) 3.0 (2006)

punster
    n 1: someone overly fond of making puns

from The Collaborative International Dictionary of English v.0.48

Punster \Pun"ster\, n.
   One who puns, or is skilled in, or given to, punning; a
   quibbler; a low wit.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

32 Moby Thesaurus words for "punster":
      banana, burlesquer, caricaturist, clown, comedian, comic, cutup,
      epigrammatist, funnyman, gag writer, gagman, gagster, humorist,
      ironist, jester, joker, jokesmith, jokester, lampooner, madcap,
      parodist, prankster, punner, quipster, reparteeist, satirist, wag,
      wagwit, wisecracker, wit, witling, zany