My son is totally shaming me as a blogger. I set him the task of blogging once a day this summer -- five sentences about anything -- and darned if he's not doing it. Of course, he's motivated: I told him that if he did his daily writing through the start of school, I'd buy him a song on iTunes that I've been saying "no" to. I thought I was pretty safe. But he's writing, and that makes me happy, too.
If you're looking for a summer writing project for your kiddo, a Blogger blog's not a bad idea. Free, easy to do, and it looks like something when they're done. I'm probably more impressed with my son's blogging than he is, but that's because I can barely drag my pixels over here to blog once a week or so. Show-off.