Another brilliant piece of Mac OS X software that was recently ushered out the gate: Fantastical. It specializes in fast, elegant calendar management via a natural language engine and event creation hotkey (assignable by you). It’s similar in concept to something like 37signals’ Backpack calendar, but far more sophisticated in its understanding of semantic syntax.
Rarely can you mention Mac OS X software without noting the developer’s carefully crafted website for it. Fantastical’s product page is great (another reason I hope these pages outrank Apple’s proxy pages for the iTunes/App Store listings in organic search), with an enjoyable subtle use of modern HTML5/CSS3 animations for product feature emphasis and clarity.