In the past I have produced HTML5 Phonegap application, TextByNumbers, for android. Last month I spent some time working on a native android application I was interested to see what challenges it would present and how it would differ from an HTML5 application.
I needed to get through the development lifecycle quickly, from start to the play store was only four weeks. I think that its resulted in a useful tool as well as giving me a much better understanding of native android development.
The tool is called MeasureMe, the app is in the play store and the code is on bitbucket. Its a low friction personal measurement tool. The measurements it currently supports are focussed on pain, sleep or energy diaries.
The workflow is that the user creates as many alarms as they need and hook them up to measurement scales, when the alarm goes off its just a simple swipe to record the measurement. The measurement is recorded in a csv text file and can be easily emailed for analysis in a spreadsheet.