NaviServer is an extensible web server suited to create scalable web sites and services. Originally based on AOLServer (http://www.aolserver.com), the ongoing development is now done independently under Mozilla Public License by a core group of people that use it for their businesses and by everyone who is willing to provide support of any kind.
Features: High Performance Multithreaded Architecture, Massively scalable and extensible, Many modules, Interpreted Config File, Dynamic scripted Pages (ADP), Caching Functions (static files, Tcl byte code, chunks), Pooled Database Connections, Thread Global Arrays, Introspection Commands, Mass Virtual Hosting (no server restart), Watchdog restarts failed Server, Control Port and Command Mode, Efficient handling of down-/uploads with async I/O
Core developers: Vlad Seryakov, Stephen Deasey, Zoran Vasiljevic, Gustaf Neumann
Source: http://bitbucket.org/naviserver/naviserver/ Info: http://wiki.tcl.tk/naviserver