I bought the mini muffin tin at Wal-Mart for $4.50 and the rest was all stuff I had lying around. Since this is a muffin tin, I'll be putting little candies behind each number for my kid(s) to have as they count down the days.
I cut out the squares of red/green cardstock (and used my corner rounder punch to round the corners) and then cut out circles - sadly, I don't have a circle punch, so I had to cut these out by hand :( Then I mod podged the papers and numbers together. Once that was dry, I added embelishments to random squares with ribbon, brads, eyelets and little paper punched shapes.
Final touch, add the magnet squares to each corner on the back.