A simple heap memory allocator in about 230 lines of C
I remember years ago my friend was gong to college for CSCI and had to write a malloc for a course. He procrastinated till the last... night... and wrote it. In the free() routine, he simply wrote "return true;". The TA's unit-tested code because there were over a hundred classmates to test. Well, the unit-tests must not have been very good because he said he scored a 100.