On some UNIX systems, there is a calendar utility which acts as a reminder service and which reads entries from files specified in tab-separated format, e.g.:
01/01\tNew Year's Day
01/02\tBank holiday in Scotland
01/25\tBurns' Night in Scotland
02/14\tSaint Valentine's Day
03/01\tSaint David's Day in Wales
03/17\tSaint Patrick's Day in Northern Ireland (also a bank holiday there)
Are there any graphical or text-based user interface calendar programs which support this format?