Frank Warren created an art project in which people write an anonymous secret they have never told anyone on a blank index card and mail it to his home. Then, he posts them on his blog, PostSecret, with a new batch of secrets going up each week.
There are also PostSecret books, lectures at colleges, museum exhibits, an iPhone app, and websites in other countries. Check back every Sunday for a new set of secrets.
If you want to submit a secret the project, you can follow these instructions:
"Reveal anything - as long as it is true and you have never shared it with anyone before.
Create your 4-by-6-inch postcards out of any mailable material. If you
want to share two or more secrets, use multiple postcards. Put your
complete secret and image on one side of the postcard."