Appropriate grades or age groups:
Elementary School
Middle School

Estimated time to complete project or implement technique:
varies

Materials needed (if applicable):
A dictionary or a parent's good vocabulary...

Project instructions or description of technique:
Choose a new word each week, and put it on your refrigerator. If your child is learning parts of speech, focus on nouns for a while, adjectives, etc. As they get older, the words can be more intellectual in nature, but kids love learning "big words" at all ages.

Encourage the whole family to use this word in sentences throughout the week. See if anyone spots it in a book, newspaper or online. Talk about synonyms and antonyms of the word, if applicable, and if your child is old enough or reading well enough, encourage them to learn how to spell it by the end of the week.

Other suggestions or comments:
Review Words of the Week occasionally, and encourage your children to use the words in writing assignments.

Consider finding the French or Spanish or other language equivalent of some of the words, and have your family learn those as well.