Well, I have the reputation about blogging around the clock, but every year more and more bloggers take that idea literally and they do it for one day for good cause, as a part of Blogathon.
Bill explains:
The mechanics are simple: bloggers sign up to blog for their chosen charity, and sponsors pledge either a lump sum or an amount per hour blogged. The goal is to blog for 24 hours straight, with one post every 30 minutes.
Over the past few years, more and more bloggers have been signing up and raising substantial amounts of money for good causes. Sign up here, then blog all day on the 28th of July and make a difference.
A Blog Around The Clock 
I’m blogging for Blogathon again for the 3rd time. This year I’ll be supporting the Association for International Cancer Research and will be blogging about cancer for 24 hours straight.
Thanks for mention about Blogathon. We definitely appreciate the publicity.
Thanks, Bora! We (my wife and a friend run it; I fetch and carry as directed) certainly do appreciate the publicity.