StreetComplete is a wonderful Android app for contributing to the OpenStreetMap project:

https://github.com/streetcomplete/StreetComplete

The UX is good enough that my five year old can use it (with a little help to read the rarer, worried quests).

Seriously, check it out. It took contributing to OSM from "painful thing I do occasionally from a sense of duty" to "fun hobby I look forward to doing and sharing with my kids."