Some have asked about yesterday's picture with the bazillion spiderwebs. We always called them Parachute Spiders. Every fall we'd see white blobs about the size of a dime, floating through the air, and know that the spiders were migrating. I've seen them 10 or 20 in one group, but I've never seem them floating in the kind of volume it would take to coat our lawn the way they did a couple of days ago.
Here's a video of a similar occurrence, from October of 2008 (I couldn't tell where this was shot). I've found reference to Ballooning, which pretty accurately describes the phenomenon.
I couldn't find a reference to specific species of Parachute Spider. From this article, it sounds like all of them are at least capable of floating away on the breeze. Cetainly, E.B. White knew about them...
They're definitely TERRIFFIC