Here is the long due sample for writing custom activity designers utilizing the freeform activitydesigner. This is still a very crude sample, so we will try to post improved versions from time to time. Thanks to Arjun for the Executors and Validators. The validators show a false positive sometimes because of a bug that we will be fixing soon.
here is a preview of the flowchart workflowtype get http://www.thispointer.com/workflows/FlowChart.jpg