I worked a the Kennedy Space Center in the late 90's on a replacement system to launch the Shuttle (was canceled because the Shuttle was being canceled). Anyway, I remember them finding a bug in the software in place at the time that was decades old. I don't remember the exact nature of it but luckily it didn't affect the actual launching.

For those unaware... In maths and physics (along with others I suppose) i, j, k are standard vector spaces. Just sayin...