I just installed the latest version of the wonderful Steel Bank Common Lisp system. Version 1.3.4 is mostly a bug fix but there are a couple of enhancements and an optimization. You can read the details on the NEWS page.
The SBCL development team generally releases a new version every month so the system is well maintained and up to date. I say it every time but it’s still true: if you’re looking for a really excellent, free (as in beer and freedom) Common Lisp system, it’s hard to do better than SBCL.