The University of Nottingham (my employers at the time) started using Concur's online travel & expense management system towards the end of 2010. They needed a simple method of accessing the Concur system from their travel and expenses documentation (hosted in Confluence) without additional authentication prompts.

A SAML-based single sign-on plugin from Confluence to Concur was rapidly designed and built over the course of a single week. Here's a demonstration of the basic functionality:

http://www.youtube.com/watch?v=4sML2RAhqig

The workflow for the plugin is essentially the same as the primary SAML use case, except that we skip steps 1 & 2 in the diagram below.

In this case, Confluence acts as the Identity Provider and Concur is the Service Provider. When you click on the "Sign in to Concur" link in the video step 3 of the workflow is initiated.