There are a number of different kinds of Calendar puzzles as you can see from the this image.

Pentominos are shapes composed of five connected squares, and there are 12 distinct shapes, often referred to by the letters L, T, V, Z, N, F, X, W, P, I, Y, and U. The calendar that I implemented only uses 10 of these shapes (X and W are omitted).

The Calendar part is laid out in a grid showing all of the months, days of the week, and days. If it's not already obvious the daily goal is to place the 10 Pentominos onto the calendar so that only today's month, day of the week, and day are showing. 

Based on one of the many designs online I 3D printed the one you see pictured above. Now I have a confession to make. While I still think this is a pretty cool puzzle, I find that I just don't have the patience to solve it every day, even though I'm retired now and have the time.

So the software developer in me kicked in and I wrote a Python script to solve the puzzle given a particular date. I was a little surprised to find that for a given day there were many different solutions. I could pick one of the solutions and apply it to my physical calendar, but why stop there! I extended the script to include some nice looking graphics (IMHO) and put together a Raspberry Pi based frame with a built-in display to show them off. The frame shows todays date and loops through all of the solutions found showing the "virtual" Pentomino arrangements for each solution.

If you follow the Instructable I posted you will be able to make your own Lazy Mans Pentomino Puzzle Calendar. Note that the Calendar needs to have a Wi-Fi connection in order operate.