Hm, interesting evening. I had resolved to go to bed extra early tonight since I've lost way too much sleep over the past week or so. Put on Steely Dan's Two Against Nature while in bed, and ended up still awake by the end of it and in a rather morbid brooding state due in part to the music. Got up, kept the lights off in my room, and wrote a decent poem about getting nowhere in life.
Was still feeling very gloomy after that, and not at all tired. Did some situps/curls for a few minutes, then put on trance music and danced nonstop for about half an hour, until drenched in sweat and feeling awesome. Pretty well played for a random weeknight.