Health Graph App Ideas

Spectator app
Fitness-tracking smartphone app; allow users of the app to follow RunKeeper Live and RunKeeper Races Live users along their race or activity path from their mobile phones.
Food trackers
Use the nutrition end-point of the API to help populate users' daily nutrition intake.
Foursquare/Twitter/Facebook & RunKeeper Mashups
Use your imagination to create a mashup app!
Hypertension app
Website or device that enables people to track blood pressure over time.
Sleep disorder app
Website or device that allows users to track sleep, sleep quality, etc.
Diabetes app
Website or device to let users track Glucose, Hemoglobin, Insulin, and C-peptide levels.
Cholesterol app
Website or device to help people track weight, body fat percentage, LDL Cholesterol, and HDL Cholesterol.
Cycling-specific app
Website or device for cyclists that tracks speed, elevation distance, xPower watts, Average Power watts, Work kj, Bike Score, Daniels Points, Training Stress score, Daniels EqP watts, TRIMP Points 1 to 10 score, Cadence rmp, Aerobic Decoupling (%), and normalized wats (associate with GPS points).
Running smartphone apps
Apps that complement the RunKeeper mobile app by providing a unique feature set to users.
Health Graph widgets for users' websites and blogs
Widgets that could take a number of different forms; for example, a widget that lets users display their personal records on a running blog.
Games
We aren't game developers, but maybe you are (or want to be)! Create a game that lets users earn points or move up levels based on changes in their Health Graph.
Android platform widgets