The town I live in has a nice centrally located community area called the town green. I've been watching the light in this area for a while and finally had an opportunity to shoot some photos right after sunset. That means I happened to be there at about the right time and coincidentally had my camera. :-)
There's quite a bit of light around when you leave the shutter open for 20 seconds as you can see from this photo, even at 9:30 or 10pm on a summer night.