RemindMe is one free, an open source application for desktop systems running Windows that will remind you of all important anniversaries, tasks, appointments and anything you want.
Calendars aimed at desktops are somewhat rare and so most people who need reminders use either cloud-based or cloud-based solutions. schedule warning emails to themselves or work with the calendar app on their mobile phone.
If instead of the above solutions you prefer an application on your computer that works offlinenetwork, without syncing your contact list and other personal data, you might want to take a look at RemindMe.
RemindMe is an open source desktop calendar application for Windows. The program is minimized when it starts and you can access it by double-clicking its icon in the taskbar. It has a sidebar and a tab bar at the bottom.
With RemidMe you can set reminders by entering a title and selecting the date and time of the reminder. Reminders can be set to repeat every day, only daily, per month or on specific dates. Of course you can add a note to the reminder.
RemindMe lets you choose any MP3 or WAV file to play at the time of the reminder, but you can also use the built-in soundof Windows.
You can view all your created reminders at any time, preview a reminder, make a copy, delete a reminder, postpone it, go to the next date, turn it on or off. It even has a countdown timer to receive a reminder in no time.
The application has a built-in one mode that allows you to run a Windows batch file (.Bat) when the reminder is activated. This is an interesting way to automate various tasks.
The pop-up notification size can be customized. RemidMe lets you customize width, height, title font, pop-up description font. You can even see the changes you have made in the notifications window as a preview before saving them.
RemindMe is a C# based application. It is only available as an installer, meaning it is not available portable version. You can download from here.