Required: Just your time.
Some of your child's best tales might actually begin in print and become masterpieces of the oral tradition. First, cut out articles from a newspaper or magazine that you've already read. Then, ask your child to select, say, a dozen words -- more or less depending on your junior storyteller's skills. He or she can either cut out or circle the words. Your child studies the words for five minutes (provide a dictionary if necessary), then weaves a story using those terms, in any order.
As a variation, you might provide additional rules. For example, your child must use the words in alphabetical order, use each word twice, or may only use words that begin with vowels.
If a gaggle of kids is available, let each player have a turn spinning a story using the same words. Then compare the tales. Alternatively, the first player "collects" a dozen words and weaves a story, the next player clips a dozen more words and continues the tale, and so on. See how long players can keep this newspaper chain story going.