If you are clever with graphics software you can probably set up a grid of numbers and pop them into this calendar. Since I’m not clever, I just printed it out, hand wrote the numbers and scanned it back into the computer. Yeah, I know it’s old school but it works and it was quick.
Teachers used to put these calendars up on the chalkboard since so many school activities revolve around the seasons and holidays.
These are easy to use in your sidebar. The April umbrella calendar I’m using now has a width of 300px and you can grab it for yourself by clicking on the image. It will open in a new window and you can save it to your computer.