MIT Game Lab's OpenRelativity toolset, which powered its psychedelic first-person collection game/physics demonstration A Slower Speed of Light, is now available for free through Github. The toolkit works in both free and paid versions of Unity.
OpenRelativity allows for the real-time simulation of principles such as time dilation, Lorentz transformation and relativistic Doppler shift by allowing the designer to augment the ways in which light behaves. As it turns out, light moving at the speed it normally does is pretty dang essential to our world not transforming into a disorienting funhouse where cause and effect are meaningless. Who could have guessed?