Is there a simple "Hello World" for making games?
Solution 1:
One fast and easy option is Quickly.
Creating a project is as easy as typing this at terminal:
quickly create ubuntu-application my-new-project
See this intro video.
Also this is a great site: http://developer.ubuntu.com/get-started/
And, of course, the manual: man quickly
You will be using python which is also great for 3d games, see Panda3D.
Solution 2:
Blender can make a 3D Game with Python: http://www.blender.org/features-gallery/features/
Is posible to make a simple hello world game there, its fully integrated with Sound, Physics simulation, GLSL, plugins for a lot of things (Networking and Web plugin included), good and professional workflow.
3D Platformer: http://www.youtube.com/watch?v=BGqyvX4P6Pg
Features Demo: http://www.youtube.com/watch?v=SjFGDcGcEjE
Panda3D its cool, but its not a Game Engine, its a bunch of Python Library where you can assemble a Game Engine, but its not fully and seamless integrated.
Ogre3D its like the same, its not a Game Engine, its just a 3D Graphics engine, where you can assemble a Game Engine, you have to code your own Sound for example.