James Raggi, publisher of Vornheim, posted the special offer on the Lamentations of the Flame Princess promotion page on Google+, saying:
Did you hear that Zak S was a consultant on the new edition of D&D? Did you hear that a free D&D basic rules PDF was released last week, and he’s credited in there?
To celebrate the achievement, we’ve made his Vornheim PDF Pay-What-You-Want over on DriveThru/RPGNow until the World War Three episode of Doctor Who airs here in Finland! (15:10 Finnish time Wednesday)
Vornheim, if you didn’t know, is the award-winning RPG supplement that details both the city of Vornheim (featured on the webshow I Hit It With My Axe) and a plethora of tools to make running improv city adventures a breeze!
Vornheim was previously bundled in the Bundle of Holding Old School Revival bundle.