This is a simple application showing how you can mount multiple Sinatra applications into a single process. It utilizes the builtin Rack middleware, URLMap. I use a simple RackUp file to launch the server, though you can probably do this in a single file.
thin -R config.ru start
or
rake start
I've extended this example to show how with a shared base class between 'apps' you can easily share configuration options.
This sample now includes a sample set of RSpec tests using Sinatra's new recommended test method, Rack::Test. I've also fixed a few issues bringing it up to compatibility with Sinatra 0.9.3