Here are a list of presentations on ActivityStreams. Feel free to add your own if it deals directly with the ActivityStreams effort or technology.
Activity Streams, Socialism, & the Future of Open Source by Chris Messina, presented June 1, 2010 at Open Source Bridge in Portland, OR.
Activity Streams by Monica Keller.
ActivityStrea.ms: Is It Getting Streamy In Here? by Chris Messina from SXSW 2010.
Video discussion of ActivityStreams from September 2009.
Early talk on Activity Streams by Chris Messina from December 19, 2008.