A number of new public beta builds are available from the ExpressionEngine team. The first of which is a new beta for what will become ExpressionEngine 2.0.
Changes in this build include can be found here: EE 2.0 changelog
The second beta is for the discussion forum module and the changes for this can be found in it's changelog.
Last but not least, the final beta is for the multiple site manager and, like the others, the updates can be read here.