Lark is a scheme-like programming language whose parser is designed after the paper Higher Order Functions for Parsing, and whose semantic evaluator is influenced heavily by the MetaCircular Evaluator from the SICP.
It has extensive and tight integration with the Objective-C object system, allowing the creation and mutation of the entire object graph, from defining new objects, to defining new classes whose method implementations are provided by lambda expressions; your entire program is a mutable entity to Lark.
The entire language was developed during over the course of 2 days at MHacks and unveiled yesterday. It is currently open source and on Github. Warning: the code is extremely messy,
https://github.com/nateburgers/SnarkDemo/tree/master/SnarkDemo