Carl Sagan Blog-a-thon
In Joel's words;
"If you're a Sagan fan with a blog, you can participate by posting something related to him on or near that date. Read or reread a Sagan book and review it; discuss cool things that you've done that's been influenced by him; pontificate on one of the many topics he treated (SETI, astronomy, critical thinking, the history of science, human intelligence....), or post about something completely surprising".
read more here
Also, see what Nick Sagan has to say about it here
And here's another Carl Sagan blog.