Cleet is a fully object-oriented, garbage-collected language for developing applications. It compiles a program down to an executable file, which runs at full machine speed -- there is no interpreted bytecode involved.
Documentation is available which describes tha language. You'll need a Mozilla-based browser or Safari to read it (IE and other KHTML-based browsers don't handle XML well enough).
Cleet is available as a source tarball. You'll need to have a garbage collector -- such as the Boehm garbage collector -- installed on your system. Cleet is known to work on Linux, and will probably work on other more-or-less POSIXy OS's.