While it is always fun to highlight and demo neat new features for our upcoming releases, like JavaScript Remoting or piloting Apex REST, it is also good to note some of the fundamental changes like updates to the API. Starting with version 22 of the changes, here's a few key points:
Of course, these points don't cover major changes like the Chatter API Developer Preview. And if you want to try out that Apex REST API so that you can roll your own REST framework – just give us a ping.
For more information on all the goodness coming down the pipe with Summer '11, check out the Summer '11 Release Page, which goes into all the new major features, and provides link to the release notes PDF as well as the recent webinar.