How to deploy your code from GitHub automatically
shinyplasticbag.posterous.com
shinyplasticbag.posterous.com
Better alternative: use something like Capistrano to automate deployments. It's not Heroku-style automatic after a push, but it's pretty close.
Still, points for ingenuity.
I agree though, this is still a really simple way to automate deployment.
For example, at work, we have a similar function that pulls down the current SVN repository onto the web servers. We've been doing this for years, it works great - but that doesn't mean people can just call these URLs from the outside. I also believe choosing an obfuscating name for the update file is not sufficiently secure.
Me, I do something vaguely similar, but using Dropbox instead. The webserver is running on a git repo that is in a Dropbox. When I commit and push to the repo (locally) the webserver picks up the changes automatically.