Abstract: A calendar system comprising a user interface having: a century table; a weekday table; an optional first lever channel; and an optional second lever channel. The system also includes a first window in the user interface substantially adjacent to the century table; a second window in the user interface; a third window in the user interface substantially adjacent to the weekday table; a year table piece, having a century indicator that is movably displayed in the first window; and a year table, seven columms of which are movably displayed in the second window. A month/date table piece is also included, having a date table, seven columns of which are movably displayed in the third window; and a month table, seven columns of which are also movably displayed in the second window; an optional first lever coupled to the year table piece through a first lever channel in the user interface; and an optional second lever coupled to the month/date table piece through a second lever channel in the user interface.