Being that the millenium is a big thing this year, maybe you could do
something with the three distinct calendars of those 3 cultures.
Here's a start - this is a clickable Roman calendar, with lots more info.
After looking at how "auspicious" dates are important in these calendars,
you students could identify events / seasons in their own lives that are
meaningful to them and design their OWN calendar for the year around them.
Considering what you've told us about your students, that could be
interesting! Not a traditional art lesson, but calendars are an almost
universal example of the importance of visual communication.