Splitwise - Splitwise is a free tool for friends and roommates to track bills and other shared expenses, so that everyone gets paid back. On the web, iPhone, and Android!
BreezoMeter - Health-focused Environmental Intelligence
Splittable - Shared living made simple
World Air Quality Index - Air quality index for the globe
EquiTable - Split the bill fairly
Flow by Plume Labs - The smart air quality tracker to help you find clean air