While it is a departure from most of what is in my blog, another of my interests is Greek and Roman siege engines – check out the following link for images of siege engines like onagers, oxybeles, gastrophetes, etc.
See the Roman Siege Weapons Page at
http://www.frapanthers.com/teachers/white/roman_siege_project.htm
The links on this page are particularly interesting – just when you think you have seen it all – you come across a list of links that includes a computer program to help you refine the design of the trebuchet you you have been building.
The link at the top of the page to a gallery of Greek and Roman siege engines is particularly nice – nice clear images that make it easy to understand how the devices worked. http://www.frapanthers.com/teachers/white/siege_gallery.htm
Here is another page on Ancient Greek artillery technology, including Archimede’s Architronio Cannon -