For those of you poliparsers in the Bay Area on July 11, we are hosting a Hack Day that allows you to get your hands dirty with the Freebase platform.
Of particular note is that we are going deep on our new server-side templating system, ACRE. Also notable is the new "MQL extensions" feature which allows you to query Freebase and then use the results to query other open APIs with a on the web joining the results. I believe this should have particular utility for unifying the many disparate projects in open government.
If you are interested, please RSVP at the link above.
Co-founder & Enfant Terrible, Metaweb, Inc.