MicroCalendar is a Windows system tray popup calendar.

It is small, unobtrusive, and always ready so you can easily check calendar dates without messing up your computer's system time or having to use a resource-intensive application.

Features an attractive user interface, a tray icon that shows today's date, displayable week numbers, copy-date-to-clipboard, and form persistence (remembers where you put it last on your screen). This calendar doesn't contain any extra, unneeded features to clutter it up or weigh your computer down; no journal, no scheduling, appointments, or alarms -- it's JUST a reference calendar, elegant and simple.