Splash is an open-source video-mapping software (for Linux and OSX), targeted at multi-projector installations such as fulldomes but which works well for smaller installations too. It has been thought as a part of a broader pipeline, so it concentrates on video-mapping and leaves content creation to other software through multiple means of communication.
Splash is open-source (GPL) so it can be hacked and re-hacked to your liking. You create a UV unwrapped 3D model of your display surface, then Splash will take care of projector calibration, including the lens parameters, color correction and multi-projector blending. Splash can be used for multi-projector installs, and has been tested displaying on up to 8 projectors simultaneously.
Go download the code and make something awesome.
See Splash in our tools listing as well.