Mint.... A full and detailed financial app that keeps track of all accounts, income and spending. It really helped us manage our money a lot better.
Cozi... A family calendar that everyone in our family has on their smartphone (all old enough to have one, 3 in total). Things scheduled are color coded to each individual or the entire family. Alerts and reminders go out to each person required. Each person can add events and can view everyone else's schedule. Really helps with families with multiple parents/kids hvaing to go all over the place.