My watch does this (shows an exciting pattern of rays) eight times a year: on the two solstices, the two equinoxes, and the four 'cross-quarter' days between those four.
(So does kleinbl00's.)
This one reminds me it's Imbolc or Brigid's Day or the beginning of spring. It also tells me it's full moon RIGHT NOW (as does peering out of the window).
It's traditionally a time for feasting, which goes nicely with eightbitsamurai's Grubski challenge. It's also considered a time for spring cleaning (natch) and setting goals into motion which goes nicely with rezzeJ's recurring goals thread. The first day of spring also happens to coincide with the latest Pubski thread.
Solstices and equinoxes are observable astronomical phenomena; cross-quarter days can be calculated from those observations. For that reason alone, I think of them as more important in the year than those odd, floating special days some traditions cherish. They're fixed by invisible threads in the latticework of the year as planet whirls around star.
What markers are special in your year? How do they prompt you to think about time? Do you experience it as an eternal round or a linear march?