a) I want some macros to use for JVM-based projects
b) I like using Emacs + SLIME (it's the best development environment, period).
Unfortunately the noise of Rails fanboys migrating to it with their usual laundry list of complaints ("no IDE support", "no good web framework") is annoying. I have nothing against Ruby in general (in fact I really like the language) and Rails in specific (I know people who love it), but the whole reduction of programming languages to merely web frameworks is a setback for software engineering. That mindset has now been spreading: not only is it impossible to hear about Ruby without "Rails" mentioned next to it, it's now common to hear "Python/Django" and "Scala/Lift".
Web is just a UI layer, a fairly mundane and boring part of an application. Lisp has very little to show for these sorts of applications, but has a lot to show for more science/engineering intensive ones. You hear all the time about webapps being re-written into PHP and other blub languages, but the community is interpreting it as a setback for the languages (and an argument in favour of using blub from the start) rather than the fact that advanced language features make really little difference for web development.
Enclojure (NetBeans)
Counterclockwise (Eclipse)
La Clojure (JetBrains)
The other thing that has really improved immensely is "project management" (right term?) provided by Leiningen. Now you can basically do "lein new proj_name", then edit a simple config file in the created directory and do "lein deps" to get all the packages that you referenced.(Doug Hoyte disagrees with me on the vi point, arguing in his book that Lisp is expressive enough not to require any editor support. I respectfully disagree.)
A web framework is still useful, even if many people assess a language purely in terms of it.
HN, what other projects do you do to familiarize yourself with a new language?