If this has already been fleshed out, and I just haven't found the topic, please forgive me. I have many friends around the world who use different calendar systems, such as the ISlamic, Hebrew/Jewish, Persian and others. I'm not talking about the ability to convert between iCal, Gmail and Microsoft Exchange calendars etc. Is there an app for such conversion? I see an app for the Islamic calendar itself, but I'd like to find one which will actually convert between calendars, showing today's date in several systems as well as a calendar view where I can enter a date in order to convert it between calendars.