Nothing beats a shady spot and a good book to beat the summer heat. Short stories make for an enjoyable light read, and I happen to know of a few that are free all weekend long, until midnight August 2:
DysFictional 4 is free on Kindle until midnight tonight (July 30)
A collection of short stories by Mandy White, ranging from odd and creepy to downright weird. Free until August 2.
A paranormal-themed collection of short stories from the twisted minds of the Writers, Poets and Deviants group. Free until August 2.
A collection of holiday tales from the writers of WPaD. Free until August 2.
A second collection of holiday tales from WPaD; not just Christmas, but other holidays as well. Free until August 2.
A grisly little cat-astrophe occurs when a man finds himself paralyzed and his seven cats are getting hungrier and hungrier… Free until August 2. 
West Coast Review 