I think a good example is the last level (Hollywood) from www.microcorruption.com, which has self modifying code and is set up such that the actual execution ju

I think a good example is the last level (Hollywood) from www.microcorruption.com, which has self modifying code and is set up such that the actual execution jumps into the middle of what the disassembler thinks are actual instructions. Reading the code is pretty useless, but with a trace of instructions executed and register state at each instruction it's easy to start at the end and follow backwards to the interesting part of the program. Getting the trace is the tricky bit, I had to write an msp430 emulator. (Actually seeing this example requires completing the rest of the levels, but you should do that anyway, especially if this is the sort of thing you're interested in)