ev3OSEK is a platform for LEGO Mindstorms EV3. It is a partially portation of the nxtOSEK platform, that is used for the older LEGO Mindstorms NXT devices. Now with ev3OSEK you can develop programs for the newer generation called EV3 using the C programming language and OSEK as the underlying realtime operating sytem. The wiki is a good starting point for more information.