Recycling Calendars

Before you go out and buy a 2007 calendar, check and see if you have an old calendar from any of these years: 1906, 1917, 1923, 1934, 1945, 1951, 1962, 1973, 1979, 1990, or 2001. For any of those years, the days are the same as in 2007.

Bonus: Here's an Excel workbook that shows substitute calendars for 1901-2030 (a very nice-looking pattern emerges).