What are some of the most fun ways you've played a game outside of how the developers intended?

I distinctly remember playing Pilotwings 64 with Gameshark most of the time. Instead of completing mission objectives, I used to use infinite fuel cheats and just explore most of the time. Birdman mode was cool, but it didn't give you the sheer control that the Rocket Belt did. I probably found most of the easter eggs in that game, including warps and the Kennedy Space Center in Florida. I'd go as far as to say that this was my first open world game, well before I actually played any. Me and a friend also had fun wrecking the Gyrocopter in certain levels. We'd see who could do the most spectacular crash. This also was, of course, before games like this came out, such as the crash mode in Burnout.