I'm currently developing a workout application for the US Navy and built this as a demo to show off the power and simplicity of Ionic + Cordova. It's a great starting point for seeing some of the correlation between Ionic, Angular and various Cordova and JS plugins.
It features a slider to set a goal, shake to start and pause, as well as an Insomnia plugin to keep the device from going to sleep while the timer is running.
Obviously not an incredibly useful app as it stands but it's a great place to get started fooling around.