Arch Linux is an i686-optimized Linux distribution. It is lightweight and contains the latest stable versions of software. Packages are in .tar.gz format and are tracked by a package manager that is designed to allow easy package upgrades. Arch is quite streamlined compared to some other distributions. Things that are relatively unused are not kept (info pages, for example). A default Arch install leaves you with a solid base; from there, you can add packages to create the custom installation you're looking for. Arch has a package build system that allows you to easily create your own packages, which makes it very easy to rebuild a package with your own custom configuration. Arch also aims to use the newer features available to Linux users, such as reiserfs/ext3 and devfs.
knock is a server/client set that implements the idea known as port-knocking. Port-knocking is a method of accessing a backdoor to your firewall through a special sequence of port hits. This can be useful for opening up temporary holes in a restrictive firewall for SSH access or similar.
Pronto is a framework consisting of loosely-coupled layers designed to handle the mundane elements of Web development without sacrificing the developer's overall control of the project. It is a PHP4/PHP5 MVC framework that supports robust dispatching, CRUD scaffolding, transparent data caching, i18n, flexible ACLs, and much more.