Book writing is coming along, and I actually can see light at the end of the tunnel. The biggest section left to write is on tensor analysis, and the biggest difficulty is determining how much to include in my book -- tensor analysis isn't that broadly used in optics, and I don't want to take up precious page space on it. Beyond that, I've got 3 or 4 other small sections to write and/or complete, and they're the fun ones. With the pressure off me a little bit (and exams graded), I'm planning to write a history of science post later this week.
In the meantime, today we officially declared that we're going to keep Sophie, the hyperactive foster kitty we picked up last month (right now she's sitting in my lap, demanding attention.) I managed (through pure luck -- my photography skills are lacking) to get a cute pic of her inside the Christmas tree, planning to demolish it: