The sound of a dial-up modem firing up (WTF actually makes that sound, anyway?) - yeah, I know, some people still have dial-up, but you people are a dying breed.

The sound of gears grinding as you're trying to shift into 1st gear in an unsynchronized car transmission while the car is moving (yeah, I know, it's a bit esoteric, but WORK WITH ME HERE, EH?????

)