Virgin America coupon: Second passenger flies free with round-trip purchase

At Virgin America, buy a select round-trip flight in the main cabin and get a second ticket (also in main cabin) on the same flight for free via coupon code "DIGGNATION". It's the best such offer we've seen from Virgin America, although we've seen a 25% off coupon (still active). Flights must be booked by December 7 for travel between November 26, 2007 and March 19, 2008.