my workshops about developing blogs and websites for classrooms I always make the point that you should add some content that will appeal to all students and parents when they visit the homepage. This content can include links to handouts, a calendar of due dates, and current announcements. Another item that you can add without taking up too much space is a countdown timer to an important date like the start of a vacation. Here are three countdown calendars that you can add to your blog or website (note, none of these work in the new version of Google Sites).
It's Almost is the simplest of the countdown calendars in this list. To create a countdown calendar just go to the site and complete the phrase, "It's Almost..." and then select a date. You can get the embed code for your calendar by clicking "share this" below the running countdown that is displayed immediately after you choose the countdown target name and date. It is important to note that when you embed it into your blog, you must display it at a size of at least 275px wide or it will not work.
TickCounter is another simple countdown calendar service. It offers a little more customization than It's Almost offers. You can customize the colors for the display title and the numerical display in the countdown. When you embed a TickCounter countdown calendar into your blog, it is automatically resized to fit in the space allotted by your blog's template.
CountingDownTo offers the most customization options of the three countdown calendars in this list. You can customize the layout design and the color scheme for your countdown calendar's display. And the display is mobile-friendly. The downside to CountingDownTo is that it does add a watermark to your embedded calendar unless you subscribe to a CountingDownTo paid plan.
Applications for Education
When I was in the third grade my teacher, Mrs. Turkington, had two countdown calendars on the wall near the chalkboard. One calendar represented the number of days left in the school year and the other represented the number of days until our next "special event" (those events were birthdays, field trips, or school assemblies). Today, Mrs. Turkington could put those calendars on a classroom blog's homepage.
(Side note, Mrs. Turkington is now retired and living in Florida. We became Facebook friends 30 years after she was my teacher).