ChristianAudio.com offers a free Christian audiobook each month. This month's selection is Augustine's Confessions. Instructions on how to order are available on the download page.
What I didn't know is that they also have a page where you can browse all of their free offerings. Desiring God has many free sermons there, including Holy, Holy, Holy Is the Lord of Hosts, a sermon on Isaiah 6 which John Piper preached at the beginning of the year one year about God's glory, and another sermon which is quite timely, given the upcoming Olympics in Beijing, How Then Shall We Run? Olympic Spirituality.
P.S. If you know of any other Olympic sermons or other resources, throw me a link in the comments. The kids are very excited to watch them, and I'd love to capitalize on that excitement in our worship time.