Can I host Drupal alongwith Google App Engine? I am new to Drupal as well as Google App Engine. I want to create a scalable website with few specialized apps in Google app engine and integrate with Drupal. Given both the platforms are extensively used, it seems to me that they should be supporting each other. However, I checked both Google app engine and Drupal website but could not figure out if they support each other. So my question is , is there any way I can host Drupal with Google app engine? Can they work together in the same platform?
Google App Engine now supports PHP, yes you can. 
But Drupal technically is supposed to run on an Apache server (.htaccess rewrites, restrictions and options) with normal email servers that can be handled using normal PHP's mail(), and PDO, you will need to take care of providing alternatives for the services. 

Mainly, GAE has limitations in emails, SQL, and writable file system. 
Here is a link to a post that helped me a lot: http://blog.boombatower.com/drupal-google-app-engine