Refer to the following recordings for examples and inspiration of what you can do with the InDesign SDK and scripts.
 

InDesign desktop SDK samples

 

Adobe (May 11, 2009)
IDML is an XML-based file format that enables developers to programmatically assemble and disassemble InDesign documents using standard XML tools and without having to open INDD files.
Adobe (May 11, 2009)
See how to build InDesign UI components such as dialog boxes and panels using Adobe Flex Builder.

 

 

Adobe (May 11, 2009)
Learn how to add rules to the new Live Preflight system with InDesign CS4 using C++.
Adobe (May 11, 2009)
This sample covers the new links architecture in InDesign CS4.

 

InDesign Server SDK sample

 

Adobe (May 11, 2009)
This recording shows a reference implementation of a text editor that can integrate with traditional publishing workflows, using standard web-based protocols.