Test Yourself: Are you a Windows Workflow Foundation Expert?
K. Scott Allen has posted 10 "hard core" WF questions to ask a job candidate. I haven't done a job interview with someone and asked him about WF, but it was nice to evaluate my knowledge of the technology. If you're using WF on a regular basis, I suggest that you take this "test" and catch up where you are missing some information. The list of answers can help.