MPX is a technology which allows multiple independent pointers (mouse cursors) at the windowing system level. By this, we mean that these mouse cursors are all connected to one single computer. This technology features the additional of multiple input devices and are ideal for various projects like: games which involve more than one player, two handed drawings, some sort of quizzes where users use one single computer etc.
The following is a screen shot of where the MPX technology is used:
The following is an informative video about this technology: http://wearables.unisa.edu.au/mpx/videos/mpx_demo.mpg