Announced two days ago is the new M-LOK System from Magpul... "M-LOK is a modular locking accessory mounting system that is a direct attachment method for hard mounting accessories to a negative space mounting point. Designed by Magpul Industries as an evolution of the MOE slot system used since 2007, the M-LOK system is being released as a free licensed platform to allow greater compatibility of accessories between all manufacturers."

You can download the full info here.