Setting production|development mode at runtime?

I have several sites that run out of the same Rails directory (I use
differentiate). Is it possible to set the production|development mode
according to SERVER_NAME at
run time? Ideally, I’d like to have the site I’m working on in
development mode, and all the rest
in production mode (instead of putting all sites in development mode, or
restarting everything
after every change in production mode).


Yahoo! Mail - PC Magazine Editors’ Choice 2005