We recently put together a 'stable' tarball for people to try out.
This code is not for the faint of heart, though, as it might require a
bit of messing around with the config to get it up and running.
However, there's lots of fun stuff to try out, if you're so inclined.
The tarball is posted there. Read the README.developer to see how to
build it. Also, if you're having problems with the config files for
htdig or BDB, try using the files from a version 3 build. Good luck!