Rack::Offline for Ruby, and optionally Rails, (written by Yehuda Katz) looks like it does that, though I haven't actually used it: http://github.com/wycats/rack

Rack::Offline for Ruby, and optionally Rails, (written by Yehuda Katz) looks like it does that, though I haven't actually used it: http://github.com/wycats/rack-offline http://github.com/wycats/rack-offline