As a freelance composer, I have a fairly casual relationship to weekends and holidays — yes, the kids are more likely to be underfoot and in need of parental tending, but otherwise I'm in no obligation to not work just because of the calendar.* But I do reserve a special status for one day, Leap Day, a day of catching up on lost time or accumulating some time on credit, a day which seems to me to allow some exemptions to routine, to invite, if not celebrate, the exceptional. Also, because its anniversaries get tucked away into some tiny curled-up dimension of Calabi-Yao spacetime (okay, they don't really do that, but they do get somewhat hidden by the ambiguity of having either or neither an anniversary every one AND/OR four years), there is both a certain freedom of operation and the luxury of a longer rhythm of recall. In any case, the extra day in the calendar is not one to be wasted. Here's a minor example: In one of my pieces, I included an alternative version of one movement, to be played in place of the standard version only in Leap Years, and also an alternative version of that, to be played only on Leap Days. (No, there is not an alternative for Leap Seconds, but that would be taking things to an interesting, and minimal extreme.)
* I am also unable to manage composing within regular working hours, but my tendency towards ever later nights — being most lucid (if I'm ever lucid!) in the hours adjacent to midnight — has been tempting me towards adopting some kind of segmented sleeping schedule,** just to have some coordinates the family can predictably share with me. One of my teachers, La Monte Young, and his partner, the visual artist Marian Zazeela, have adopted various non-standard schedules over the years, usually with more than 24 hours in a day, and they have done this for decades with admirable discipline. But the constant cycling in and out of phase with the rest of the working world strikes me as having more practical disadvantages than is worth.
** Some historians believe that segmented sleep was in fact typical of the pre-industrial era, a first sleep with four or so hours down, then an hour or two of waking, followed by a second sleep til morning and a nap or siesta at midday. The insertion of that waking period between the two sleeps strikes me as sensible, real private time outside any institutional rhythm.