Build an app for multitaskers that sends an alert when there is a significant play in the football game your watching. All you have to do is look up from your other task when your phone plays the selected sound. The revenue stream could be an ad in the tone and or the icon. The sponsor could be somebody like Charles Schwab or Starbucks.
Advantages: Easy to build an MVP. Easy to roll out. Built right it would be very sticky.
Disadvantage: Low barrier to entry.
Yes “multitasker” is a word in Websters. “Multi-tasker” is also acceptable.