The LabLog is a free tool to document projects running in a lab and to manage experimentally obtained data and its metadata. LabLog interfaces to a mySQL database that stores this information. Allows easy searching and retrieval of once recorded data.
The Skydiver's Online Logbook is a feature rich way to inventorize your skydives. It has a database driven backend, which allows you to do lots of interesting queries and basically datamine your logbook, and those of other people using the logbook.