Fantom is open source under the Academic Free License 3.0 and is available for Windows and Unix-like platforms (including Mac OS X).
Experimental programming language No. 7: Zimbu
Most programming languages borrow features and syntax from an earlier language. Zimbu takes bits and pieces from almost all of them. The brainchild of Bram Moolenaar, creator of the Vim text editor, Zimbu aims to be a fast, concise, portable, and easy-to-read language that can be used to code anything from a GUI application to an OS kernel.
Owing to its mongrel nature, Zimbu's syntax is unique and idiosyncratic, yet feature-rich. It uses C-like expressions and operators, but its own keywords, data types, and block structures. It supports memory management, threads, and pipes.
Portability is a key concern. Although Zimbu is a compiled language, the Zimbu compiler outputs ANSI C code, allowing binaries to be built only on platforms with a native C compiler.
Unfortunately, the Zimbu project is in its infancy. The compiler can build itself and some example programs, but not all valid Zimbu code will compile and run properly. Not all proposed features are implemented yet, and some are implemented in clumsy ways. The language specification is also expected to change over time, adding keywords, types, and syntax as necessary. Thus, documentation is spotty, too. Still, if you would like to experiment, preliminary tools are available under the Apache license.
Experimental programming language No. 8: X10
Parallel processing was once a specialized niche of software development, but with the rise of multicore CPUs and distributed computing, parallelism is going mainstream. Unfortunately, today's programming languages aren't keeping pace with the trend. That's why IBM Research is developing X10, a language designed specifically for modern parallel architectures, with the goal of increasing developer productivity "times 10."
X10 handles concurrency using the partitioned global address space (PGAS) programming model. Code and data are separated into units and distributed across one or more "places," making it easy to scale a program from a single-threaded prototype (a single place) to multiple threads running on one or more multicore processors (multiple places) in a high-performance cluster.
X10 code most resembles Java; in fact, the X10 runtime is available as a native executable and as class files for the JVM. The X10 compiler can output C++ or Java source code. Direct interoperability with Java is a future goal of the project.
For now, the language is evolving, yet fairly mature. The compiler and runtime are available for various platforms, including Linux, Mac OS X, and Windows. Additional tools include an Eclipse-based IDE and a debugger, all distributed under the Eclipse Public License.
Experimental programming language No. 9: haXe
Lots of languages can be used to write portable code. C compilers are available for virtually every CPU architecture, and Java bytecode will run wherever there's a JVM. But haXe (pronounced "hex") is more than just portable. It's a multiplatform language that can target diverse operating environments, ranging from native binaries to interpreters and virtual machines.