AV or not AV?
They asked people to fill in a ballot paper just as if the election was being held under the Alternative Vote system (AV).
Now, some of you might say that they should get out more - but if you're interested in a large-scale reconstruction of what would have happened in Parliament, read on.
Seventeen thousand people took part in the experiment and it found that AV would have made a critical political difference.
In the 2010 election an AV vote showed that a Labour/Lib Dem Alliance would have been more likely.
Lib Dem gains
Professor Paul Whiteley explains: "It showed that Labour would have lost around 10 seats compared with the actual outcome.
"The Conservatives would have lost around 20 seats and the Liberal Democrats would have gained just over 30 seats.
"The numbers aren't large, as after all there's 650 Members of Parliament but it would have made a Liberal Democrat/Labour coalition a possibility.
"They could have had a majority on those numbers had the election been held under AV. So it would have been politically quite consequential."
Under AV in the eastern counties Labour would very probably have retained a couple of the seats it lost and the Lib Dems may have made modest gains.
In such a Conservative-dominated region the changes would have been more modest than elsewhere.
"The AV campaign has not really ignited. A 60% turnout on 5 May would give the result legitimacy," says Professor Whiteley, "but if it is down in the 40% region or even 30%, it will be very difficult.
"If the 'No's win, it will put to bed the issue of electoral reform for years to come because people will point to this and say there wasn't sufficient interest."