schema map is a Web-based Oracle database explorer. It caches meta data about all tables, columns, triggers, constraints, indexes, and sequences, and allows you to view all tables that are FKed to a given table, or that have a column containing the same name as a given column. A number of persistent query buffers can be edited, cleared, and run with a single click.
recurrance takes a date recurrance expression in near-English, and returns all the dates that match. For example, entering "the second and last friday of every month" might tell you all the dates on which you should get paid. It is very explible and easy to use, and complies to RFC 2445 RRULE implementations with the exception of BYWEEKPOS, WKST, and the start and end dates, which are done using the code interface. It also supports an XML version of RRULE, includes tests, and is completely self contained.