well, i joined a stepbet. You bet on yourself (games are $20-40) and they draw your steps from your fitness tracker and create a daily goal for you to meet 4 days, then a higher "stretch" goal for 2 days. Its based on where you are, so someone who runs every day currently will have a higher goal than someone who is currently sedentary. If you meet the goals for the duration of the game (2-4 weeks), then you split the pot at the end. If you don't make your goal any given week, you lose your money.
So, I guess it works - to get my stretch goal for today, I stayed on the treadmill an extra 15 minutes. So, I guess its doing its job. Just need to keep it up for another 4 weeks!