'App' is a preprocessor for C++ that accepts as input arbitrary C++ code that may contain embedded constructs for specifying algebraic data types and associated pattern matching operations, and produces as output the same code with all such constructs translated to normal C++. What app essentially does is provide for C++ pretty much the same capabilities that functional languages have regarding algebraic types. 'Applib' is the associated runtime library that supports the core run time requirements of the translated code, and which provides additional utilities (applib is covered by the LGPL).
GNU Aspell is a spell checker designed to eventually replace Ispell. It can either be used as a library or as an independent spell checker. Its main feature is that it does a superior job of suggesting possible replacements for a misspelled word than just about any other spell checker out there for the English language. Unlike Ispell, Aspell can also easily check documents in UTF-8 without having to use a special dictionary. Aspell will also do its best to respect the current locale setting. Other advantages over Ispell include support for using multiple dictionaries at once and intelligently handling personal dictionaries when more than one Aspell process is open at once.
auth_ldap is an LDAP authentication module for the Apache Web server. Auth_ldap has excellent performance, due to its use of aggressive client-side caching algorithms. It also has support for LDAP over SS or TLSL. It also features a mode that lets Microsoft Frontpage clients manage their Web permissions while still using LDAP for authentication.
Bayonne is the telephony server of the GNU project. It offers a script-driven threaded multi-line state event telephony service on GNU/Linux, xBSD, and Microsoft Windows for building voice response systems, and uses telephony plugins for runtime driver configuration. It also features "TGI" for making Perl applications "telephony aware". It may be used to build telephony-based system administration, home automation, automated attendant, v-commerce, and voice messaging systems.