I call this the "woman lackadaisically using it while staring at her phone" machine.
As all existing audio players for swimmers are shit, when I swim laps, I have lots of time to think.
Idea: Chess swimming – like chess boxing, but with swimming. Embed waterproof touchscreens in one vertical end of a lap pool. A swimmer moves pieces between laps, playing against a computer or against someone with whom he or she is sharing a lane.
Idea: Embed waterproof touchscreens in both vertical ends of a lap pool. On one end, a swimmer reads a multiple choice trivia question, which he or she answers on the other end. Then he or she swims back to receive another question and so forth.
Swim trivia should be an Olympic event. 4 question x 100m medley. You keep swimming laps until you answer four questions correctly. Fastest to do so wins gold.