Boo is an object oriented statically typed programming language for the .NET and Mono runtimes with a python inspired syntax and a special focus on language and compiler extensibility.
A good way to start is by reading the Boo Manifesto and following the Primer to learn the language step by step.
Note
The Boo Primer is also available in Traditional Chinese (繁體中文), translated by Yan-ren Tsai aka Elleryq.
The english version is downloadable in PDF format.
For a more detailed explanation about the features in the language check out the Language Guide.