Welcome to shikadi.net, a site primarily dedicated to "classic games" - those from the early 1990s that ran on a PC under MS-DOS.
The DOS Game Modding Wiki is hosted here, which aims to document the file formats used by these games, as well as tools that can be used to examine and modify the games.
There are also a few game-specific sites hosted here, including the Commander Keen Wiki and archived copies of older fan sites.
See the sidebar on the left for more.