A simple tricorder for Android, using your phone’s real sensors to detect magnetic fields, gravity, etc. Detect buried powerful magnets! See the passing gravity wave from a distant collapsar on your phone screen!† Be a mega-geek! Etc.
Tricorder is a Trekkie geek toy that turns your Android phone into a Tricorder. However, it’s not totally a toy, as it uses real data from your phone’s sensors — you may be surprised at how many sensors your phone has. Currently it can display acceleration; the local magnetic field; an analysis of the local acoustic environment; your location from various providers; the availability and strength of cellular and WiFi signals; and the current state of the Sun and solar wind, including current pictures of the Sun.