Neal Gafter recently gave a presentation at JavaOne and Jazoon '07 entitled "Closures for Java". The presentation is an accessible but thorough introduction to closures, the goals, the problem with existing solutions, all presented in a conversational style.
Yesterday at Java One Sun finally announced the first implementation of JSR-1, the Real-time Specification for Java, since it was finalized in July of 2006.
In today's Java One keynote Sun announced that the open sourcing of Java has been completed. There is now a completely build-able JDK available to developers at the OpenJDK project.