http://www.sleepycat.com/

http://www.businessweek.com/technology/content/feb2006/tc20060209_810527.htm

As the second article states, on first impressions, this doesn't appear to make much sense.

I can't see the appeal of open source databases -  MS SQL offers all I need, and is free in basic form

http://msdn.microsoft.com/vstudio/express/sql/default.aspx

With this version, there is no governor (unlike 2000), and it can support 1GB RAM and 4GB database size