See the downloads page for this long-overdue update to Nu.
The most visible change in this release is that the macro operator has been switched to refer to macro-1 instead of macro-0 (the original Nu macro facility). That is deprecated but kept for compatibility.
Support for garbage collection is now compiled in by default (Mac OS only).
We've also been making good progress running Nu on Linux-based systems. Currently a few small sites (including Tim's blog) are running with Nu on Rackspace Cloud Servers. See notes/DEBIANINSTALL in the Nu source distribution for details about building for Debian.