I participated in this read-a-thon last year and it was a lot of fun, so I'm participating again this year!
It's hosted by My Shelf Confessions and here are the basics:
The Wicked Wildfire Read-A-Thon is a time when we all get together to dedicate the days of July 14-24 to as much reading as possible. You read as much as you can in order to get yourself a little further through that huge to-read pile! We know real life gets in the way and even if you can’t participate more than one day, you’re welcome to join in on the fun!