Maya!

Microsoft Outlook, part of the Microsoft Office Suite (not to be confused with Microsoft Outlook Express), is a personal information manager that lets you manage your e-mail, calendar, contacts, and tasks.

Keep track of your busy schedule and share it with others using Calendar. Create separate calendars — one for home, another for school, a third for work, and so on. See all your calendars in a single window or choose to see only the calendars you want. Calendar lets you create invitations using information from Contacts, update your guest list, keep track of responses, and receive the latest status information. When you or another Mac user receives a Calendar invitation via Mail, it’s automatically added. Calendar also works with iCloud, Yahoo!, and Google. And when you use iCloud, every Calendar edit you make on your Mac automatically appears on your iPad, iPhone, and iPod touch. So no dinner dates are missed, no meeting goes unattended, and no anniversary is forgotten. »

Fantastical is a flexible calendar with natural language event creation, a beautiful calendar and event list, support for CalDAV (including Google Calendar delegates) automatic alarms, and instant searching.

An offline calendar without any other calendar integration. You can easily create recurring events and setup reminders, it can also display week numbers.

California is a new calendar application for GNOME 3. It's currently under heavy development.

CalenGoo gives you a fast and easy way to access and change your Google Calendar (or Google Apps Calendar) with your Android device. It can either work with the built-in calendar or it can sync directly with Google.

BEAUTIFULLY DESIGNEDDigiCal’s diary planner and organizer provides a clear and beautiful overview for your events and appointments.• Conveniently switch between 7 calendar views (day, week, week agenda, month calendar, text month, year and list view in portrait and landscape mode).• The slick dark theme allows for better visibility in low-light settings and night mode.• Event keyword image matching available in all 27 languages!• 6 highly customizable widgets with different theme styles and views: (FREE: list, day, day list, day grid widgets; PREMIUM: 2 extra widgets –text month and month calendar widget)• Intuitive navigation between days, weeks and months with zoomable day and week view. »

You can view an entire month or focus on a specific date and time.

MemoCalendar.net is a light-weight and easy-to-use online calendar like a usual memo calendar on the wall. Behind every day a small note can be deposited. MemoCalendar.net is free and without registration (login) usable.

Caliander is the calendar that lets you create events faster and with less effort while keeping you on top of things with its smart and unique presentation. It uses the same calendar database as iCal, so it syncs with all your devices as usual, and all your events are there—no migration needed!

MineTime is a free, modern desktop calendar app. Connect all your calendar services and let MineTime's Scheduling Intelligence help you optimize your time.MineTime works natively with Google Calendar, Outlook.com, Microsoft Exchange and Office 365: this means you can organize all your calendars directly in MineTime.