From the right, a newly released CBS news video feed from September 2008 showing Katie Couric lambasting the names of Sarah Palin's children, Trig and Track ("Where the hell do they get these [names]?"), is being used by some conservative groups to demonstrate Katie Couric's bias against all things conservative ("Couric's Palin vid leaked"). What is lacking is experimental control, a film of Couric reaction to the unusual names of a liberal's kids, perhaps Calc and Econ. Even then the number of observations would be so small to make a strong conclusion.
From the left, James Harrington, a pastor, set up a mock fight between two black men to test the reaction of an invited speaker, a white police officer ("Police: Officer Baited In Altercation That Injured Him"). Again there is no experimental control. How would the same cop react to a fight between two white men?
We can't always make decisions on controlled experimentation, but we should be careful about the conclusions we draw without it.