The Mojave Experiment

The Mojave Experiment is an advertising campaign by Microsoft for the Windows Vista operating system. The participants in the experiment were asked about their perceptions of Windows Vista (having never used it) and then were shown a ten minute demo of Microsoft's "next OS", codenamed "Mojave". After the experiment was over, it was revealed that "Mojave" was actually Windows Vista. Before the session, the average rating of Vista was 4.4 out of 10; after the session the average rating was 8.5 out of 10

Check out http://www.mojaveexperiment.com/