I love love love biking at night. It is so quiet and cool. The lights are pretty, the ground seems to move faster under my headlight. The streets are empty of cars.
I live with 3 housemates, I constantly offer to go to the store for them or whatever, any excuse to get out at night. If you haven't tried it, go out there. I like having to go get something, the existance of some alterior motive just makes me push it harder. It's especially nice after a long day, when you think you don't have any more go left in you...very refreshing.
[/rambling odd post]