I had a smaller intentional gap in 1992 after MTDP folded which I used to bicycle to the Worldcon in Orlando (well, really to Richmond VA, because who wants to bike any further south than that in August) and one when I left MIT in 1996 which is how come we could get set up for a housewarming party in the new place in DC so quickly. I used a bunch of vacation time while chairing Arisia 2006 around the time of my 5-year anniversary at Permabit and I suspect a formal sabbatical then would have been eaten up by Arisia, as was the couple of weeks I had between jobs at the end of 2006. I conclude from this that three weeks is not enough time to do more than catch up on the metaphorical laundry.
And so it is my plan to spend August on sabbatical. I will be employed on the 1st and the 31st but not in between. I've already booked some travel into this plan, but I hope to make major progress on some personal projects. Four and a half weeks is not as good as six but hopefully it will do.