objSQL is a PHP-based database access layer for multiple database servers. Primarily designed for small-to-medium projects, it uses an "Object Based" approach for handling general database queries. Built-in support for transactions and prepared statements allow for a common interface to all supported database types. Recordset paging is simplified by incorporating the paging method along with many helper methods for general queries. objSQL is easily extended to create your own unique classes and methods.
Auto Multiple Choice (AMC) is a piece of software that helps you to create and manage multiple choice questionnaires, with automated marking. Tests can be written in plain text or LaTeX. Automated correction and grading is performed from scans of the answer sheets using optical mark recognition.
Ackr is a very small subset of grep/ack/rak, for lazy developers. grep is a great tool, a very powerful tool, but often too powerful for simple needs. Ackr looks for a search string in all text files and in all subfolders from the working directory, is case insensitive, has no options, doesn't look into hidden folders/files, and displays the search term in a bold font.
QMentat helps you practice mental arithmetic. It uses arbitrary-length fixed point arithmetic, and can handle any size numbers, only limited by the size of your screen (and in the case of division with an integer result, the speed at which the number can be factored). It is also quite configurable, allowing you to tailor the questions to your needs.