The captcha.php library is very user-friendly and extremely easy to integrate into existing forms, because of its simple API. It nevertheless sports many configuration options, like multiple image modes and accessible alternative text riddles. It also has "AJAX" super cow powers and many sensible defaults to frustrate users less than other implementations. It prevents spambot access well, even with its relaxed defaults.
DHCP Lease Query in PHP is a PHP class that will allow you to send DHCPLEASEQUERY packets to inquire about known leases from a remote DHCP server. It is similar in nature to ISC's OMAPI but without the hangs it creates, nor does it cause dhcpd to behave in a single-threaded fashion while talking to it. After all, it emulates an actual DHCP "helper" (relay agent) and, as such, all queries travel over IP. It is based on RFCs related to DHCP and follows the RFCs as closely as possible.
Redstart Templating implements a template engine which supports template inheritance. It can process templates based on PHP code loaded from given files. It can use class variables or local variables to define values for template placeholders. It supports template inheritance, including additional inline templates, and it can be extended with plugins.
PHP CLI Framework is a simple class which you can extend to quickly create a commandline (CLI) application using PHP. Only a single file is needed, and everything extends that file. It supports interactive input and an object oriented way of writing which keeps things nice and clean. Features include arguments, flags, options, colors, interactive input, object oriented PHP5, a micro framework, and minimal coding required. There's only a single class to extend.
File upload and validation class is a PHP class that can be used to validate and process uploaded files. It can validate a given uploaded file by checking its MIME type or its original file type, and by checking its file size against a given limit and file type. It currently supports audio, video, PDF, and image file uploads. The class can create a path in the server as well.