Boo
The Boo language lives somewhere in between IronPython and C#. Though Boo supports duck-typing, it is still a statically typed language. Boo has a flexible, Python-like syntax. Constructs such as closures may be implemented with a block or brace structure. Parentheses are not required for function or method calls. These features, and others, have allowed Boo to gain popularity as a language for implementing DSLs.
License:
Boo License
Project Home Page:
http://boo.codehaus.org/