Yumpee pointed me to an old story about a guy who used a BBC Micro monitoring a decaying prawn sandwich to tell the time! Jockey is a cool user-space program execution recording and replaying library for Linux. It actually scans the code page of a process to recognise system call instructions and rewrites them to jump to a trampoline instead. By the way, my favourite Free 3D modelling tool Blender has reached version 2.40 featuring tonnes of cool improvements.