One of my favorite spontaneous recreational pastimes in college was biking around Cambridge at night. Sometimes I'd go with a few friends who were into spontaneous nighttime activities in general (I don't mean any innuendo, just that they'd do things like, oh, look for fences to climb over or buildings to sneak on top of or build longbows out of crutches). Sometimes by myself. The great thing about Cambridge was that I never learned the geography well enough to know where I was going 100%, but I could always find my way back: I'd end up at a recognizable intersection without knowing exactly what direction I'd taken to get there. There were hills, but not too many; traffic would be light on any but the most major streets. And I never felt in danger of getting accosted or accidentally riding into a bad neighborhood.
Here, I live on the edges of a not-so-great neighborhood. The drivers are unskilled, to say the least, to the extent that riding in daytime, I tend to defer obsequiously at intersections even when I have right of way. There are trolley tracks that run down major streets and buses that tend to cut you off, and I think I mentioned the crazy drivers.
Tonight was the first night this year I felt the urge to hop on my bike and head off somewhere - it had that spring flavor - but when I left my house to return a DVD, I got in the car instead. Sigh.