One of my favorite email subscriptions is to A.Word.A.Day -- a day-to-day collection each week (gathered by Anu Garg) of five related terms to learn anjoy. On April 15, I learned the new word arithmomania -- and quote the following from Garg's posting.
arithmomania PRONUNCIATION: (uh-rith-muh-MAY-nee-uh)
MEANING: noun: An obsessive preoccupation with numbers, calculations, and counting.