Picax is a AJAX photo gallery which will use the XML format from Google’s Picasa Album to display exported albums on your own homepages. It has features as multiple albums, slideshows and by using google maps it can display where the pictures were take
A mod_perl-based RPC API designed for ease of setup, ease of extension, and rapid development.
Using Presto, you can develop a robust, fully "web-2.0" web application in a day or two.
Oh and it scales.
Take that, Ruby on Rails.