When I get more specific details, I'll be sure to post, but the Downeaster's website isn't reflecting 2011 dates yet - I've confirmed the V773 Buy One Get One Free code for the Downeaster only is at least valid throughout January, 2011, possibly the entire year as has been the case in the past.

The code in 2010 was subject to blackout dates and was only valid on trains 681, 683, 686, 688, 691, 693, 694, 696, and 698 (in other words, late afternoon/evening departures Southbound, morning departures Northbound).