1. This person needs a way to comply with the law, while still getting stereo sound! The law (riding with at least one ear uncovered) is intended so that bikers could hear traffic coming. (Maybe a way to solve this is to have a microphone attached to the headphones, and selectively pass through only loud noises (car horn, people yelling, etc.) to the speakers.)
2. This person needs a way to secure his MP3 player better. Sport pants are quite baggy, and so they swing around a lot with the MP3 player there.
3. This person needs a way to get encouragement through his earphones while he's running.
4. These people need a way to talk to each other without having to take their headphones off.
5. This person needs a way to secure her MP3 player without having to hold it.
Verplank diagram
