MPS 2.0 Milestone 5 is out
MPS 2.0 M5 is out, the New and Noteworthy
is available. The highlight certainly is the debugger support for debugging MPS with MPS. This obviously helps you track down problems in your language. M5 also comes with a type system tracer that helps you better understand the unification that's used to calculate types.
One more Milestone, and the final release should be out end of June or beginning of July. Great stuff :)