PHP Template Inheritance consists of a handful of functions which allow child templates to inherit common structure from base templates. Multiple levels of inheritance are possible. The inspiration for this project was Django's template inheritance mechanism. Templates are PHP files too, so you can do (almost) whatever you want in them.
Sputnik is a content management system (CMS) designed for extensibility. It works as a wiki out of the box, but can be extended into other things. It offers editable nodes, history and diff, user accounts with optional email validation, a flexible permission system, RSS feeds, and more. Sputnik supports access control and has editable templates. It can be used to maintain a personal Web site that doesn't look like a wiki and that only you can edit. Sputnik is easy to install on shared hosting without root accounts.
mod_gfx is a configurable Apache module that uses libgd to perform image operations on the fly. Some of the supported image operations are: resize, resample, watermark, and crop. A couple of its special features are origin selection via URI regex and round-robin over a list of hosts.
RTK (Ruckus Tool Kit) is a high-performance, Perl-based, dynamic, content-generation system. It provides a nearly transparent bridge between HTML-based code pages and traditional CGI-based systems. It has been designed to automatically take advantage of existing systems, such as basic CGI, Apache's mod_perl, FastCGI, and SpeedyCGI, but does not require such systems for high-performance optimization.
Pictag is a simple web photo gallery with automatic thumbnail generation and tagging capability. It's self-contained in a single file, uses the filesystem for gallery layout, and requires no stand-alone database (it uses SQLite) or no database at all. It handles EXIF data, provides support for HTTP user authentication and authorization, and is customizable.