Luxor is an open-source XML User Interface Language (XUL) toolkit in Java that lets you build UIs using XML and also includes an ultra light-weight, multi-threaded Web server, a portal engine, and a template engine. It is also Web Start-ready, as everything fits in a jar and requires no loose files.
Factor is a dynamically-typed stack-based programming language. Factor runs on various OSes and CPU architectures, and provides an optimizing compiler, interactive development environment, powerful collections, higher order programming, continuations, and a growing library of contributed code.
Check Website is a performance monitoring and uptime notification tool. It will check if a Website is up, and check the response time of the site. The administrator can then choose to receive an email notification if the site is down, or if the site response time is too slow. All results are also written to a daily log file.
Nanoweb is a modular Web server written in PHP. It is designed to be small, secure, and extensible. It is HTTP/1.1 compliant and has decent performance, CGI and FastCGI support, a nice configuration system, name-based virtual hosts, server side includes, authentication, gzip content encoding support, Apache combined format and MySQL logging, and many advanced features.
WebCit is a Web-based, AJAX-enabled frontend to the Citadel groupware/collaboration system. It is an attractive Web middleware layer that allows user-friendly access. By combining WebCit and Citadel, you can have a versatile online environment with many users concurrently accessing the same system using the user interface of their choice (text, Web, or downloaded client software).
OWFS (One Wire Filesystem) allows easy control of the 1-Wire bus under Linux. The bus can either be viewed in a Web browser (OWHTTPD) or as files (OWFS). This makes manipulating the 1-wire devices easy with shell scripts, Perl, C, and other programming languages. 1-Wire devices are intriguing chips made by Dallas Semi. They are cheap, uniquely numbered, and take minimal wiring to connect (a data/power line and ground are all that's required. Chip functions include memory, switches, counters, and sensors of temperature and voltage.
Apache mod_suid allows per-vhost execution of scripts under their own UIDs. It functions in a way similar to Apache's perchild MPM, but differs in a number of ways. It does per child user/group switching; the Apache MPM makes switches based on vhosts. All processing is done under a specific UID/GID, including PHP and mod_perl scripts.