We hope you've been enjoying the new XMPP API we shipped in App Engine release 1.2.5. We're always impressed with the cool scenarios our developers create!
A couple of Google engineers found the time to create cool App Engine demos using the XMPP API and we'd like to share them with you.
CrowdGuru - this app, courtesy of App Engine Developer Programs Engineer Nick Johnson, is a fun trivia game which crowdsources answers. Add email@example.com to your IM list and ask it a question. You can read up on full details of the design and implementation here.
Multi-Chat - David Symonds wasn't satisfied with simple person-to-person IM, so he built an IRC-like chat room system! Add firstname.lastname@example.org to your IM list and message it "/help" to find out how you can join channels and start chatting it up. Full source is available here, and a basic web interface is here.
Of course, please note that these apps are solely intended to demonstrate the power of the XMPP API - they are not official products in any form, nor are they supported. In particular, don't send any private or personally identifying information when chatting with these bots.
But definitely try them out and let us know what cool app experiences you are building with App Engine!