If you haven't picked up a book in the Imagination Station series yet now is your chance to see what it's all about. Tyndale House is giving away a free PDF download of the very first book in the series, Voyage with the Vikings. Here's the summary: "Beth and Patrick find a mysterious letter while in the Imagination Station requesting a Viking sunstone. The letter is old and says that someone named Albert will be imprisoned if the sunstone isn’t found. Mr. Whittaker sends cousins Patrick and Beth to Greenland circa 1000. On their quest for the sunstone, the cousins meet Vikings Erik the Red and Leif Eriksson and find the sunstone as they join Leif on his first voyage to North America. But the adventure is just beginning, for when they return to Mr. Whittaker’s workshop with the sunstone, there is another note waiting for them, requesting a silver goblet. Join Patrick and Beth as they continue their travel to various lands and time." You can download it here.