Despite the fact that I have no classes before 10am, I haven't been getting nearly enough sleep in the last week, which leads my thoughts back to happy memories of better days during the summer... carefree days when I could sleep as much as I wanted.
These days are mostly a fiction, a trick of the mind, a mirage brought on by the aforementioned lack of sleep... with three days or less to see most places I visited, I didn't sleep much at a lot of the stops.
A specific memory comes to mind: my first night in Sofia, I stayed up until four am trying to help a friend figure out whether it was feasible for him to board a train to Istanbul-- I had my doubts, but he loved the idea, and when I went back upstairs to the room he stayed awake for the rest of the night, researching timetables and talking to the hostel's night clerk.
The last days of the trip, though, were fairly restful... we had all been traveling for weeks, and it was so hot in Serbia that there was almost no point in going out during the day-- so we'd sleep until noon, then loaf around, reading and watching movies, and then go out only in the evenings when the sun was low in the sky.
Moving through timezones did some damage to my internal clock, but I find that these lines are far less disruptive than the personal timezones of the hosts I stayed with-- the routine of a place has power more power to shift a sleep schedule than such an arbitrary thing as the rising or setting of the sun.