Google App Engine and Twilio challenge you to build voice or voice-enhanced applications hosted on App Engine that use Twilio's voice application API to make and receive phone calls. Twilio hosts a telephony in the cloud web service, allowing web developers to build scalable, reliable voice communications applications on web hosting platforms like Google App Engine. Put Twilio and App Engine together and you can build voice applications with features, scalability, and reliability that companies used to spend millions for. Submit your app by Oct 4th to win a Dell Netbook from Twilio and $1000 of App Engine hosting credit from Google.
More info: App Engine blog