Hour by Hour Guide
Hour by Hour was inspired by my experience of making travel plans: if I have a flight from London Heathrow at 11:30, when should I arrive at the airport? (2.5 hours before.) When should I set off from my home town? (1 hour before that.) When should I set my alarm? (1 hour before that.)
So while the app may seem primarily about keeping track of your day's schedule at a glance, it's also about quickly making time calculations by entering quick, note-like natural-language entries, and relative timing.
Above all, the app has been designed to make creating schedules as fast, fluid, and easy as possible.