Darkness on the Edge of Town by Brian Keene is today's other freebie offering with an incredibly short Product Description from publisher Leisure (the other is Nina Bangs' Eternal Pleasure; she's got a great bit of what the BBC calls Nominative Determinism going on there).
Product Description
One morning the residents of Walden, Virginia, woke to find themselves cut off from the rest of the world by an impenetrable wall of darkness.
Looks like Horror to me, and a quick skim of the frontpage customer reviews seems to agree.