we have our own version of www.moodle.org called Stream. I now have some grant money to implement a 3D game engine (probably unity3D but could be Blender 3D or similar) to run inside our STREAMed Moodle pages.

Some inspirations (and I would like to add more):

SLOODLE
http://www.sloodle.org/moodle/ : SLOODLE is an Open Source project which integrates the multi-user virtual environment of Second Life® with the Moodle® learning-management system.
SLOODLE provides a range of tools for supporting learning and teaching to the immersive virtual world; tools which are integrated with a tried and tested leading web-based learning management system.

Play Paradise Paintball – Cmune

Paradise Paintball 3D is a fast paced multiplayer FPS which mixes all the fun of paintball with counter-strike style shooter action. In single player mode, …Or run it on Facebook or as a Mac widget..

STREAM
http://stream.massey.ac.nz/

UPDATE: Well the unity webplugin can definitely run inside a Stream (Moodle) blogpost. Here is a screenshot of a 6 week 2nd year student project.