I was inspired by another credit card sized calendar that I thought had a great design, but I was frustrated that it wasn't updated for the current year. So in the maker spirit, I created my own version that will automatically update depending on the year inputed.
Download the calendar template. The calendar does require the Excel application, I have not tested it with other compatible spreadsheets.
How to use the calendar
1) Choose a day in the calendar (e.g. 21)
2) With your finger draw a line from the chosen day to the month (e.g. July)
3) The blue months have 30 days, and green months have 31 days, the orange month is for February (supports leap years).
4) To change the year, open the spreadsheet, click the year (e.g. 2012 by default), and input a new four digit year.