The new: the "so good I can't believe it is free software" DrScheme Scheme development environment has a new 2.09 version available now.
The old: over on the Lisp blogs recently, I saw a reference to the availability Xerox Parc Medley Lisp for non-commercial use. It is bundled with the LFG grammar toolkit. It is available here.
This is the Lisp that I used in the 1980s on my Xerox 1108 Lisp machine. I downloaded the Medley Lisp and LFG grammar bundle (runtime converted to run on Linux) and took a trip down 'memory lane'. (I am in bed with the flu - not well enough to work, but well enough for messing around with old software).
While I use Common Lisp for my Lisp development now, I am so happy to have a non-commercial version of Medley. Wowza!