This document provides an overview of Sugar, an open-source learning platform originally developed for the OLPC XO laptop. It discusses how Sugar is designed based on principles of learning-centric design to facilitate open-ended discovery, collaboration, and creativity for children. Key aspects of Sugar highlighted include its use of activities instead of applications, its journal/portfolio feature, and its emphasis on usability while allowing for complexity. The document also discusses Sugar's technical underpinnings and how its status as free and open-source software aligns with its goals of empowering student expression and creativity.