Salesforce.com and Adobe announced this week the Flex Toolkit for Apex which allows Flex-driven Flash applications to be integrated into Salesforce apps as first class citizens. This opens the door to a new class of rich Internet applications now delivered through an on-demand enterprise platform.
Third-party Flex applications are packaged-up and served from the Salesforce servers and so no additional infrastructure is needed. The toolkit shares the same single sign-on as the a regular Salesforce app which makes the experience more seamless. I spoke with Adam Gross, Salesforce.com's VP of Developer Marketing, who demonstrated a couple of interesting applications that highlight the ability of the Flash and the Salesforce app to exchange data in realtime: one was a drag-and-drop calendar application and the other was the interactive charts of sales data shown below.
This toolkit also supports the current alpha 1 release of Adobe's Apollo.