"simple and smooth." ... "2 years" ... long feature list... Gives a kinda contradictory vibe :)
Calendar stuff gets grotty quick, we're holding a huge set of conventions and expectations so deep that we have trouble articulating them. We know what we expect from a calendar: we can see when they fail; but its difficult to visualize or explain what they should be doing instead.
Been playing with generating calendars to help me see the darkest night hours, there's lovely libraries to do all the difficult bits for me, all my data is to hand; and I'm kinda stumped at how to show it in a form that fits into those almost subconscious conventions.