You should take a walk every single night, and try to have a portable music player available so you can listen to music while you walk. Make sure that the music is fast because most people tend to walk to the beat of the music that they are listening to.
Walk to lunch. If you work in an office environment, try walking to lunch at a place at least five minutes away. That way, after you've eaten and returned to work, you will have also done a nice 10 minute walk which can be healthy for your state of mind and body as well.