Pharo

Pharo is a cross-platform implementation of the classic Smalltalk-80 programming language and runtime system. It is based on the OpenSmalltalk virtual machine (VM) named Cog, which evaluates a dynamic, reflective, and object-oriented programming language with a syntax closely resembling Smalltalk-80. It is free and open-source software, released under a mix of MIT, and Apache 2 licenses. (Wikipedia)