Chicken is an implementation of SchemeLanguage that's inspired by CheneyOnTheMta. It's maintained by felix winkelmann. It's a Scheme-to-C compiler, but it's got an interpreter as well. It's got an easy-to-use FFI.
Even if Chicken sucked, and it definitely doesn't, it would rock. Because it has felix. -- SunnanFenderson
It's available at http://www.call-with-current-continuation.org.