Distributed Cell-Phone Based Night Surveys
Utilize billions of phone cameras, while charging battery at nights, to watch the sky for phenomena.
Many of us geeks and nerds know that long-exposure night photography works pretty well with modern phones.
So, just creating an app, that monitors the sky collecting light while charging the phone at night, that activates automatically, when plugged in to charge at night (e.g., when sensors say it's dark, battery is charging, and no significant accelerometer motion is detected, and Wi-Fi connection is used), could be used to record, compress and send astronomic data for a decentralized research of the skies. It could be run intensively, utilizing its compute and network, because at those times it would be plugged in to the grid and Wi-Fi.
The users could set up custom data servers to send the data to, and this way, collectively run night surveys. Who knows what they could discover? Undocumented satellites, UFOs, NEOs, and maybe something else that we didn't know of.