[B' Spokes: While you can use headphones in just one ear this seems like an option that might be worth considering. I will note I have no experience with this product, it just looks cool.]
In many states it is illegal to operate a vehicle (yes that includes bikes and skateboards) with earbuds in your ear.
More states are creating legislation every year. It is dangerous, however, in all 50 states and Canada. O-tus IS the solution!
With O-tus 15 watt near-ear speakers, you can hear background sounds (bikes, cars, emergency vehicles, and your friend’s whining) and have your own personal surround sound stereo. All without long chords to tangle and untangle.