I already participated in Bloggiesta a few times and am happy to see that there is a new Bloggiesta taking place end of March.
What is Bloggiesta? From It’s all about books:
Bloggiesta is a three day event where participants will spend as much time as they can working on fixing all those pesky blog related tasks…. all those things that you think "some day I’m going to clean that up, or change that around, or add that thing!"