Shareware, but has no time limits and no disabled features. Always visible on your dekstop. Calendrier permanent, an Excel speadsheet to build printable calendars with holidays for different countries, in different languages. Download it for free. In Franch and English.
Calculator tells the Aztec date of any given day.
A fair amount of overlap here but check this site for calendar converters I've missed. Your Store for Calendars, Diaries, Organizers, Planners, Palmtops and Handhelds. What you see is on the Web. You can reply with your voice to the email. Have a calendar always on your desktop hidden in a tooltip together with Julian date.