Since I have only a few spots in my yard that turn brown, I have been spot-watering those areas to save water keeping my grass green. To reduce evaporation losses, I go out after dark with a flashlight to set my little sprinklers.
So I was out in my yard in bare feet shining my flashlight and saw the yard looked like it was wet, because of all the little points of light reflecting back. I was confused until I realized it was thousands of wolf spiders all sitting on top of the grass, and the little points of light were their beady little eyes. There was probably at least 1 per square foot. I don't know why they like my yard so much.