iOS: By their nature, calendar apps tend to be a little complicated and busy. Peek is an app that simplifies your calendar down to the most essential details and uses a completely gesture-based interface so buttons don't get in the way.
Peek is a bit like Clear in that its main aim is to provide a simple design rather than a large set of features. Instead of buttons, you use gestures to get around in Peek, which takes a while to become used to.
Tapping and holding a day adds an event, a swipe views the length and location, an awkward "shading" gesture reveals the time, and everything else is done with pulls, swipes and presses. It takes a while to learn the control scheme, but once you get it, Peek works well.
That said, Peek's design mantra echoes in its features as well. For example, you can't invite people to events or get directions to them. For power-users, Peek simply won't do the trick, but if you don't need a lot of features, Peek is a bright and fun way to view your calendar.
Peek ($1.99) [iTunes App Store]