VueMinder Calendar is the best calender software for Windows.

• View and update your schedule directly on the Windows desktop using a transparent calendar.
• Create informative reminders containing event descriptions, pictures, video, music, or web pages.
• Automatically send reminders to friends, family, or coworkers via email or SMS text messages.
• Share calendars and reminders online or over your local network.
• Collaborate with multiple people sharing the same calendar.
• Tweak and tailor every facet of the easy-to-use interface.
• Automatically synchronize with Microsoft Outlook or Google Calendar.
• Easily import events, tasks, and notes from Excel, or export to Excel and many other file formats.
• Integrate calendar sharing with many other calendar applications via the iCalendar standard.