Bethesda's suite of RPGs have been discounted on Steam
-- specifically, its Game of the Year offerings. The Elder Scrolls III: Morrowind
gets the most drastic cut at 75% off, down to $5, while Fallout 3
has been discounted by 50% to $25. The Elder Scrolls IV: Oblivion
straddles the middle with a discount of 66%, down to $8.50.
As far as sheer hours-to-dollars ratio, you're probably looking at something like eleventy kajillion