Connecting the iPhone to Google’s App Engine
Absolutely loving this piece of work !

Then clicking on these summaries takes you to a detail view

Not particularly groundbreaking you might think but the implications are significant…data (the bard’s poems in this case) reside in the Google App Engine ‘Cloud’ and the heavylifting gets done by a little python scripting to get the content down to the iPhone client.
For extreme programming or agile delivery prototyping the opportunities are considerable and not just limited to the iPhone client (which was picked in this instance) it could as easily have been leveraged in a silverlight RIA or an Adobe Air.