My most viewed blog post by far, with over 500 views (yeah I know, not that many but it's a big deal for little ol' me!) is my post on Postsecret Sundays. Every Sunday I look forward to reading the latest Postsecret post.
I love Postsecret.
Search the word 'postsecret' in YouTube for more. Also, check out this post for The Secret Behind Postsecret, where one blogger actually talked to Frank Warren about some behind the scenes details.
Another good one that summarized the whole "connecting with strangers" movement: