Red Turpentine Beetle
This one smacked me in the back of the neck while I was working in the yard the weekend of May 24, and got tangled up in the hair on my upper back until I grabbed it and pulled it out.
I then noticed there were several others flying about, so they are obviously something really common. It looks exactly like a Red Turpentine Beetle, Dendroctonus valens. This is a pretty likely identification, because (a) they are well-known pests of pine trees, (b) there is a pine plantation just behind our house, and (c) they emerge as adult beetles very early in the spring.