http://markbwarner.googlepages.com/cognos_oem_links.html
Here is a good site that shows some cool things that can be done with Cognos from a developers perspective.
https://www.ibm.com/developerworks/mydeveloperworks/blogs/0a7c97bb-6cf9-4ddb-a918-80994e7b444d/?lang=en_us
It does require an ibm account which is free.