Answers in Genesis is giving away a free download of the Ken Ham vs. Bill Nye debate from two years ago. You have to go through the online store checkout process, but you don't need to create an account and you don't need a credit card. This is the "SD" (as opposed to the "HD") version, which is a 3GB DVD-quality mp4.
Here is a link to the deal page. There's a button on that page that will add the debate and a "discussion guide" to your cart and apply the DEBATE16 discount code.