Web-based Electronic Laboratory Notebook (ELN) with integrated Chemical Inventory by the group of Prof. Goossen (TU Kaiserslautern, Germany), based on PHP/MySQL. Allows (sub-)structure search, reaction planning, management of spectra and literature.
The Generic Genetic Studies Database (GGSD) is a web-based, relational database driven data management software package for the management of large scale genetic studies.
Sage is a web-based stats system for your Folding@Home team. It is light, fast, and based on PHP and an assortment of SQL-based database management systems, so it is ideal for webservers.