The Answers.com Creative Writing Challenge sounds like a fun little contest that includes the challenge of using a list of ten words they've provided. (Granted, you have to go through the linky-ness of linking to those words on Answers.com, but most contests are promos of some kind, so that doesn't bother me.) I'm going to run this one past Anne and Betsy, and see if they have any interest.
(Note: the contest appears to be open to all ages, as "children under the age of 18 may have their parents or legal guardians submit entries on their behalf.")
H/T: Hope C. Clark's Funds for Writers newsletter.