Boggle game. We used something similar at film-maker's camp for 10-13 year olds. Whatever film-making term they learned that day became the word to do a "boggle-like" activity eith. It went over very well.
Creating this into a worksheet might be something kids can grab for when they are done with work. Besides read a book of course! Or it could be used with dictionary practice to verify the words they write are really words!