So half an hour of sitting and futzing with the piano has produced a pretty neat cadenza for the end of Chopin's Nocturne Op. 9 No. 2. (Based rather loosely on some notes of Chopin that are reproduced in the back of my edition of the music, together with a rather unhelpful explanation in German, which - after deciphering it with the aid of a German-speaking friend - turns out to be almost completely incomprehensible in any language.)
And I just realized that it's only 9:30, so I can spend some time working more on this without waking my neighbors.
BTW, if anyone's been trying to reach me over e-mail today - my e-mail server seems to have been mostly down since this morning, so I haven't gotten any messages. No, I'm not ignoring you. :)