I used to hit the trail head after midnight on a regular basis. After work, I would grab my pack from home, and just go. Most of the time by myself too. In the summer it's nice not to have to walk in the heat of the day.
I hike trails that I am familiar with If I go out at night. I also have a tendancy not to use a flashlight. If there is a full, or close to full moon I would often set out with just a keychain light, and never use it.
Now I don't recomend this for everyone. I plan to spend the night out anyways, so if I were to get turned around I could just lay my sleeping bag out in the middle of the trail, and figure it out in the morning.
In the Angeles forest, particulariliy the Mt. Wilson area, If you know your antena towers you can even triangulate off of thye blinky red lights in the middle of the night. I never needed to at night, but I have during the day.
Now the one thing I will caution you guys strongly about is the area you're doing your night hike. There are some pretty weird people out in the woods every once in a while. Also animals will give me a little concern. I will not hike through canyons and dense brush at night anymore. Just after dusk me and a buddy came across a mountain kitty down the canyon from the Mt. Wilson Toll Road right before the Iddlehour cut off. Guess where we were headed. Down that canyon, and across two more. So after we tried to scare it away it left on it's own schedule. We continued, and my buddy said he saw it watching us in the next canyon over, and then in the third canyon we heard a limb snap bout 25 feet up in a tree that was growing out of the canyon slope about 20 feet down (close to eye level in other words).
So the next day what started out as a fork carved from a thick stick turned into a mountain kitty totem that we left displayed in the middle of camp. I haven't had an encounter with a big cat since.
Now, at night, I will stick to trails in the open, and on the frontside of the mountains where a mountain Kitty isn't likely to be on the prowl.
Although, my long winded butt must throw in that it is an excelent way to introduce people to hiking. Take a girl out some time, and if she trust you enough, it can be awesome. I have one trail in mind that has a long curved tunnel about a half mile from the car. Now the trail curves so all of a sudden you come around a slight bend and theres this big black hole in the side of the mountain where the trail just disapears. You can't tell it's a tunnel untill you are about 15 to twenty feet into it and can catch a glimpse of light at the other side. If you can convince her to go through that tunnel, then when you get up to the top of the mt. in another 2 miles and the whole LA basin sits in front of you twinkling, oh thats an experience to be remembered. But now I'm just reminiscing.