Blog Action Day  is a global nonprofit event that wants to unite bloggers, podcasters and videocasters around a common issue, on a specific day, to raise awareness about the topic and trigger a worldwide discussion. This year the issue is poverty and the date is October 15.
As the organizers say, poverty is an extremely complex issue that can be explored and discussed through many different lenses. The proposal is for bloggers to put up a post, video or podcast on October 15 about poverty that remains related to their regular blog topic. This may sound like a stretch in many cases, but you can see here  some good suggestions that can inspire you even if your blog is centered around something like, say, sports or design.
The official site offers many other ideas to help promote the initiative (by translating it  into other languages, for example) and contribute in more concrete ways --like donating your ad revenue  for that day. Check it all out here .