Just stumbled upon this one. 
A game and physics engine for Flash including:
- Rigid Body Dynamics
- Scene management
- Line of sight
- User Input
- Scrolling
- AI
Project home: http://code.google.com/p/glaze/
Example: http://home.planet.nl/~borst595/glaze.html
Blog: http://yaa-blog.blogspot.com/
