The Aida project is two-fold: it defines a simple common markup language designed to describe structured text, and it implements a compiler that translates the Aida syntax into various target formats (HTML, LaTeX, Trac, Mediawiki, Text, Markdown, and others). The system is fast, flexible, and extensible. The core command, aida, is a strict parser (written using Bison and Flex), which analyzes files written in the Aida Markup Language and invokes callbacks in order to convert them to the target format. It embeds a Tcl language interpreter and the callbacks are written in Tcl. This makes it very easy to extend the library and to define new target formats. Furthermore, the Aida files are highly parameterizable via a header and the entire system is configurable at the admin and at the user level. It is also possible to evaluate Tcl code within an Aida file and thus create dynamic contents.
The Role Playing Database maintains data files containing information about the players, monsters, spells, treasures, tricks, traps, etc. used in table-top role playing games, such as Dungeons and Dragons. It also provides a way to make maps of the playing environment (e.g. dungeons) in which the game(s) take place.
Scid vs. PC is a powerful chess toolkit. It has extensive database and PGN file handling capabilities, and can be used to play chess on the internet (with FICS), against a computer chess opponent, or for chess grandmasters to prepare for tournament matches. Additionally, Scid vs. PC can run automated computer tournaments with chess engines playing against each other.