Objectify-Appengine is a thin Java wrapper around Google App Engine's low-level datastore API that allows you to persist type-safe POJO objects. It provides a human-friendly query interface, generified key, query, and prepared query classes, GWT-able entity objects, and transactions in one lightweight jar file with no dependencies.
Tephlon is an easy PHP persistence library. It has a highly modular OOP design and a no-SQL storage system. It stores any object or variable safely and tidily on disk for fast access. The API is meant to be easy and fast to learn. It features Java-style key-value maps, namespaces, easy Codeigniter integration, programmable lifetime of records, a multi-driver architecture, reliable and well-tested code, and easy incremental backup of data with SVN or GIT.