The ancient Greek astronomers devised ingenious methods for measuring the size and distances of the Earth, Moon and Sun. The concepts were beautifully simple and although in most cases could only yield approximate results, they have the advantage that they can be understood by anyone with a basic mathematical background. The emergence of affordable planetarium software enables educators to reproduce these pioneering measurements in the classroom. In this paper, several activities are presented that are based on observations and experiments performed over 2000 years ago. By using freeware software students are introduced to key milestones in the history of astronomy in an immersive and interactive way.