Nirav Patel wanted to listen to music in his car, but was having trouble with the tape adapter used to plug in his phone. Instead of just switching to a FM transmitter or getting a new stereo, he decided to take matters into his own hands, and modded the stereo to enable an auxiliary input. After some incidents involving the tape player, lots of troubleshooting, and a small fire, he was able to get everything working.
I performed a similar hack on the factory radio in my own car a couple of years ago, but for a slightly different reason- the aftermarket stereos with CD players that I installed kept getting stolen. Once I replaced it with an old tape deck unit with a secret auxiliary input, no one wanted to take it!