You start out with a clock and you simply drag an icon to that clock to a certain hour. Or you let it sit on the side as to indicate it's a day-long activity.
You have the choice out of several icons at the moment, and more are on the way according to the creator. So suppose you need to get your car checked, you can choose that icon. Meeting someone for coffee, click on the coffee icon.
When you tap that icon, you enter the usual calendar mode. There you can edit things like date, hours, extra notes, place, etc.
And of course, you can see your calendar per month where a small star indicates when you have an activity, meeting, etc planned
If you're interested in getting the app, you can find it in the iTunes Store for €1.59
I am currently waiting for the update since I'm having some trouble with it. Apparently because my iPhone is in Dutch (darn language), it messes it up. I hope the update will fix that so that I can use the app fully now. Also if you're going to check the Dutch version of the App Store... then you'll see my translation. Yeah yeah
Still, I love the app and it's pretty as well. Go get it!