It's hosted by Susannah Conway , and has been going for 4 years running now. Basically, it's a month to post pictures only, with maybe a word or two, or maybe not. It's pretty free-form, you don't have to do it everyday, you can post one pic or many, etc. There's also a whole bunch of other optional components: a flickr group, an Instagram hashtag, photo prompts, a link up. But the part I like best is that they're all optional.
I'm going home to Minnesota to visit family for half of August already, so this seems like a great way to keep up, while also taking a break at the same time. I'll post a few regular posts here and there as well, but I think I'll mostly do a photo or two, especially while I'm traveling.