Some ideas seem both practical and ludicrous at the same time, as can be evidenced by this Kickstarter project: Core, a wearable Bluetooth speaker. Core is both a speaker you can use on your desk and then immediately strap on bandolier-style.
Besides the speaker, it includes a pocket to carry small items like your keys, a light for night runs, waterproofness and a mic to help you pick up calls.
To order your own Core and annoy your neighbours as you jog, just head on over to the Kickstarter and cough up the early bird price of US$90. The project has so far already been fully-funded, reaching its goal of US$11,500 with another 17 days left before its campaign ends.