Frucnatra is a port/implementation of Sinatra which runs on PHP, thanks to Fructose. And of course, it's a lot like Sinatra:

# index.rb
require 'frucnatra'

get '/' do
  'Hello world!'
end

Put this in your .htaccess:

Options +FollowSymlinks

RewriteEngine On

RewriteCond %{REQUEST_FILENAME} !index\.php

RewriteRule ^(.*)$ index.php/$1 [NC]

Make sure you have .NET 4.0 installed, and have Microsoft.Dynamic.dll and Microsoft.Scripting.dll in the compiler directory:

compiler\Fructose.exe index.rb

No docs on this yet.

Basic routes, redirect, status