Prototype Object/Relational mapper produced by MicroSoft.
The prototype and early documentation is available from http://communities.msn.com/objectspaces [MSN group seems to be dead, 2004-02-25]
There doesn't seem to be anything on the main Web site about it other than talked about in an interview extra.
Looks like it has the standard features of an O/R mapping tool, and if released could become the de facto standard for the DotNet platform.
-- ShaunSmith