rstat.us is a microblogging site built on top of the ostatus protocol.
Just do this:
$ git clone https://github.com/hotsh/rstat.us.git
$ cd rstat.us
$ heroku create
$ git push heroku master
Bam!
This is nowhere near done. Jump on Freenode and ping 'steveklabnik' if you want to contribute in some way.