Security-enhanced Linux - National Security Agency (NSA) - research prototype of the Linux kernel and a number of utilities with enhanced security functionality designed simply to demonstrate the value of mandatory access controls to the Linux community and how such controls could be added to Linux
Simple End User Linux (SEUL) - goal is to help create a computer operating environment for the average person: one that can be installed without a PhD, maintained without calling Tech Support, and used with the confidence that it will work, rather than waiting for the next crash