@vitaut That list kinda helps illustrate that games aren't (just) software -- a huge number of the entries on that list are engine clones for interpreting/playing non-Free game data, including often non-Free code in game scripts.
Naming that list "open source games" is dishonest, imo. It's like saying that Google search is open source because I can use it in Firefox.
@seanmiddleditch Maybe they should have a separate category.