I've recently been building a couple of very small fluent interfaces.  These have been focused on component testing, where some of their disadvantages aren't as important.  Let me give an example: public void PartialRecoveryFromTwoSessions() { When .SessionStartsAt("1 Jan 1990 21:25:00", s => s .MessagesProcessed(3, 5, 1)) .And.SessionStartsAt("1 Jan 1990 21:35:00", s => s .MessagesProcessed(2, 6)) .Then ...