The FFC Theme for March is alphabet/numerals. 1,000 word limit. By letters, they mean alphabet letters. This can take you anywhere you can imagine and follow any genre. The numbers can be numerals of any flavor. Arabic numerals, Roman numerals, Mayan ones. Or even some system you create yourself.
Go here for more information. Due 12:00 P.M. EST on 03/12/2008.