This past week, one of my students presented his first paper at HPDC. There is a more detailed blog entry at the research website by the student, but I wanted to mention it here too. (Post: http://www.macesystems.org/2011/06/incontext-simple-parallelism-for-distributed-applications/)
The very short story: the Mace toolkit has scalability issues since events must run atomically (think a big lock protecting events to run only one at a time). This paper describes the first step towards loosening that restriction, and running different events in parallel as long as they are not both trying to write to global state.