IronPython 2.0 was just released to codeplex for download. Here are a few important links:
The key change for this release is having IronPython now written on top of the Dynamic Language Runtime (DLR). The DLR allows multiple dynamic languages to inter-operate with each other at a type system level, in addition to giving a compiler author a lot intrinsic features that make writing a compiler a lot easier.
In addition to this change, the release contains over 500 bug fixes, including 453 reported by the community through codeplex.
Congratulations to the team on reaching this major milestone!