FLAIM is an embeddable database engine ala' Sleepycat's Berkeley DB. FLAIM is interesting in that it looks like it also provides a query language and indexing on the DB contents. Plus there's XFLAIM which looks to be an XML store on top of FLAIM. Novell has open sourced FLAIM and XFLAIM.
Wonder if there's a Python binding.
[Via Hack the Planet]