It looks like Jython is finally getting some real momentum and support - from Sun. In the past week they hired Ted Leung, formerly of the OSAF and Frank Wierzbicki, the current leader of the Jython project. Tim Bray and others at Sun pushed for this and it should be a big win for the Jython and Python communities.
Several years ago I started tinkering with Jython and I used it as the scripting language in a JNDI browsing tool that I built. It provided a nice way to connect to MQ destinations via JNDI and script test messages to the system I worked on for my former employer. Unfortunately, Jython development ground to a halt shortly after I built that tool and I decided it wasn't worth the effort to continue developing it.
Since that time Microsoft and the original developer of Jython, Jim Hugunin, have taken the idea of Python on a virtual machine and run with it. They've done wonders with IronPython. I've been hoping to see the same sort of activity on the JVM and it appears that the pieces of the puzzle are now in place. With the Jython project back on track I'll undoubtedly be incorporating it as a scripting language in my current development projects.