If you are running multiple calendars at once, things can get gnarly - Fantastical lets you customize sets of calendars to view at once, and they can even be location-based, so things don't get too crazy when viewing. You can customize your views for daily, weekly, monthly, and even yearly, and your agenda of events appears in the side bar as well. With Fantastical, you are getting a fully functional desktop app that also has a menubar version for quick access. VPN Deals: Lifetime license for $16, monthly plans at $1 & more
